How does a Christian keep the Sabbath Holy?

In context, Paul is talking about eating or not eating. To make the comment about anything else is dishonest.

Rom 14:2 For indeed one believes to eat all things; but being weak, another eats vegetables.
Rom 14:3 Do not let him who eats despise him who does not eat; and do not let him who does not eat judge him who eats, for God has received him.
Rom 14:4 Who are you that judges another's servant? To his own master he stands or falls. But he will stand, for God is able to make him stand.
Rom 14:5 One indeed esteems a day above another day; and another esteems every day alike. Let each one be fully assured in his own mind.

In context, of the culture at that time, some held fasting to certain days, some did not fast at all, and some did not eat meat on certain days. Nothing in context is about 7th day rest versus 1st day celebrating Jesus' resurrection.

I have no idea what you are saying when you "no need to follow Levitical law". The dietary law was not the law of the Levites. YHWH law =
Lev 11:1 And the LORD/Yehovah spoke to Moses and to Aaron, saying to them,
Lev 11:2 Speak to the sons of Israel, saying, These are the animals which you shall eat among all the animals that are in the earth.

The Ten Commandments and the 4th commandment (unless you are Catholic) = Deu_5:15 And remember that thou wast a servant in the land of Egypt, and that the LORD thy God brought thee out thence through a mighty hand and by a stretched out arm: therefore the LORD thy God commanded thee to keep the sabbath day.

All of Israel were commanded to keep the LORD's commandments. Not just Levites.

Exo 20:1 And God spake all these words, saying,
Exo 20:2 I am the LORD thy God, which have brought thee out of the land of Egypt, out of the house of bondage.
Exo 20:3 Thou shalt have no other gods before me.
Exo 20:4 Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth:
Exo 20:5 Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;
Exo 20:6 And shewing mercy unto thousands of them that love me, and keep my commandments.
Exo 20:7 Thou shalt not take the name of the LORD thy God in vain; for the LORD will not hold him guiltless that taketh his name in vain.
Exo 20:8 Remember the sabbath day, to keep it holy.
Exo 20:9 Six days shalt thou labour, and do all thy work:
Exo 20:10 But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates:
Exo 20:11 For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.
Exo 20:12 Honour thy father and thy mother: that thy days may be long upon the land which the LORD thy God giveth thee.
Exo 20:13 Thou shalt not kill.
Exo 20:14 Thou shalt not commit adultery.
Exo 20:15 Thou shalt not steal.
Exo 20:16 Thou shalt not bear false witness against thy neighbour.
Exo 20:17 Thou shalt not covet thy neighbour's house, thou shalt not covet thy neighbour's wife, nor his manservant, nor his maidservant, nor his ox, nor his ass, nor any thing that is thy neighbour's.

Lev 25:1 And the LORD spake unto Moses in mount Sinai, saying,
Lev 25:2 Speak unto the children of Israel, and say unto them, When ye come into the land which I give you, then shall the land keep a sabbath unto the LORD.
Lev 25:3 Six years thou shalt sow thy field, and six years thou shalt prune thy vineyard, and gather in the fruit thereof;
Lev 25:4 But in the seventh year shall be a sabbath of rest unto the land, a sabbath for the LORD: thou shalt neither sow thy field, nor prune thy vineyard.

Again this was not a Levitical law.

The Levite priesthood had duties, and in those duties some had to work on the Sabbath.

When the 2nd Temple was destroyed in 70 AD, that ended the Temple services and they were scattered at that time.

Christ died in 31 AD, so how come the Temple and the Levitical priest continued for nearly 40 years????

The whole sacrificial system pointed to Christ. Once His sacrifice was accepted by God, no sacrifice was necessary. Thus, the rules established for sacrifice became obsolete.

The laws for sacrifices did become obsolete, but the laws that define right and wrong are still there for our good.

A wall of safety.

Pro 25:28 He that hath no rule over his own spirit is like a city that is broken down, and without walls.

So your actually saying that the law became obsolete, but the law is still valid. That is a contradiction.

I think it was because God was long suffering with the Jews. They crucified Jesus and had lots of opportunities to believe (and many did), but most didn't so God let allowed them to be scattered. He gave them 40 years to believe.

Luk 24:47 And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.

There are subtle differences between these holy days.

For example, the Sabbath is a seventh day of rest.

The Passover is an event that occurs after sundown. The Passover is not a holy day. Occurs on the 14th of Nisan.

The first day of Unleavened Bread is different to a Sabbath day, in that you can prepare and cook a meal on that day. Occurs on the 15th of Nisan.

The day before a Sabbath day is called the Preparation day, because no one can prepare or cook food on a Sabbath.

There is no Preparation day for the Passover or the first day of Unleavened Bread.

So we don't act like a bull in a china shop. We read the scripture carefully.

I assumed he was referring to the book of Leviticus.

The laws involving sacrifices (the laws that pointed to Jesus and showed what Jesus would do) are now obsolete because Jesus is fulfilling them in heaven.
The laws that define sin (the 10 commandments or moral laws) are still valid because sin is still wrong and sin is still the transgression of the law
Murder, lying, adultery, coveting, taking the Lords name in vain, having other gods, forgetting the sabbath are all still sins.

Keeping the law does not save us but knowing the pain that sin has caused, i want to keep the law.

1Jn 3:3-6
3 And every man that hath this hope in him purifieth himself, even as he is pure. 4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law. 5 And ye know that he was manifested to take away our sins; and in him is no sin. 6 Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him.
Joh 14:15 If ye love me, keep my commandments.

Since the old covenant has been made obsolete, does this leave us with no moral direction? Absolutely not. God has made the old covenant obsolete to legally put into place the new covenant. (2 Corinthians 3:6-9; Hebrews 8:6-13) The life of discipleship flows out of the new command, to love one another as He loved us (John 13:34), which Paul refers to as the "law of Christ." (Galatians 6:2)

Love fulfills the law (Romans 13:8-10). Out of this single command comes other commands, including references for the moral aspect of 9 of the 10 commandments which are reiterated under the new covenant, yet the command to keep the Sabbath day is not binding on Christians under the new covenant.

1. You shall have no other gods before Me. - Acts 14:15
2. You shall make no idols. - 1 John 5:21
3. You shall not take the name of the Lord your God in vain. - 1 Timothy 6:1; James 5:12
4. Keep the Sabbath day holy. - Not binding on the Church - Colossians 2:16-17
5. Honor your father and your mother. - Ephesians 6:1-2
6. You shall not murder. - Romans 13:9-10; 1 John 3:15
7. You shall not commit adultery. - Romans 13:9-10; 1 Corinthians 6:9-10
8. You shall not steal. - Romans 13:9-10; Ephesians 4:28
9. You shall not bear false witness against your neighbor. - Romans 13:9-10; Colossians 3:9-10
10. You shall not covet. - Romans 13:9-10; Ephesians 5:3

You are still saying the law is valid and the law is invalid at the same time.

The law is declaring that you don't love others.

No matter what you do, you will not love others. If you have any integrity within, you will openly admit that you do not love others.

God is love.

All the law does is give you the knowledge of sin, nothing else. The law cannot make you righteous, the law cannot stop your sin.

In vain, you seek righteousness (freedom from sin) in the law.

A compact way of understanding the law.

Matthew 7:12
In everything, therefore, treat people the same way you want them to treat you, for this is the Law and the Prophets.

Gods laws never change I think. Jesus told us

I have not said that.
My righteousness (imputed and imparted) comes from Jesus.
It is a gift that we accept by faith.

But the law defines sin so our hearts can be convicted and moved to give up what is wrong (lawless) and accept the laws that are love.

If i do not understand that bowing down to graven images is wrong, i will do it ignorantly. Today the sabbath is made known to us so we should not be claiming ignorance.

I not sure how much clearer i can state it....

There are more then one laws
If there are 2 different laws, one can be void and the other can still be valid.

If there were 2 trees, one can be dead and the other tree can still be alive.

There is one set of laws referred to as 'the law' in the New Testament. Below is an extract from that one law.

Leviticus 19:13-14
You shall not oppress your neighbor, nor rob him. The wages of a hired worker are not to remain with you all night until morning. You shall not curse a person who is deaf, nor put a stumbling block before a person who is blind, but you shall revere your God; I am the Lord.

Are you telling me that you can put something on the ground, so that a blind person can trip over it?

I would assume your saying that. You can do that because there is no law protecting blind people.

That's not a sin?

Anything that that is not of faith is also sin.

The love of money will cause you to fall away, the love of money is sinful.

There are many things that will cause you to stumble in the world.

The ten commandments are a poor guide to the spiritual walk.

Jesus is the perfect example of love.

The law is founded on love.

If we were all 100% loving we wouldn't need a law.

But we are all sinners and all of us have fallen short of the glory of God.

When the Holy Spirit controls our actions and thought we do not transgress the law.
Jesus was never selfish and always obeyed the Spirit.
Jesus perfectly obeyed the 10 commandments.

Rom 8:1-5
1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit. 2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death. 3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: 4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit. 5 For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit.

Rom 13:8-10 KJV 8 Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law. 9 For this, Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself. 10 Love worketh no ill to his neighbour: therefore love is the fulfilling of the law.

Love is the fulfilling of the law... love thy neighbour as thyself is a summary, a brief summary of the law.

It should be written on the heart, it is spiritual. Rom 7:14 For we know that the law is spiritual: but I am carnal, sold under sin.

The love of money is a sin too. The Ten commandments covers that sin.... no. 1 and no. 10.
Exo 20:3 Thou shalt have no other gods before me.
Exo 20:17 Thou shalt not covet thy neighbour's house, thou shalt not covet thy neighbour's wife, nor his manservant, nor his maidservant, nor his ox, nor his ass, nor any thing that is thy neighbour's.

You'll find the 10 commandments are a divinely inspired set of laws.

God did write them.

Getting back to the question.

How does a christian keep the sabbath holy?

By prayer and suplication.

Ask God to guide you and study the treachings He has already given.

But Jesus is the best example.
Phi 4: 6 Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God. 7 And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus.