It’s the same for someone being saved in the first place as it is for someone who is already saved:
Simply put, believe in the gospel of Christ, repent of evil, obey God going forward.
What this actually looks like in context of the Bible is that those who Christ was telling to believe in him were being instructed in the ways of righteousness with the hope they would follow these ways because they are required.
John 8
51Very truly I tell you, whoever obeys my word will never see death.”
John 14
23Jesus replied, “Anyone who loves me will obey my teaching. My Father will love them, and we will come to them and make our home with them.
24Anyone who does not love me will not obey my teaching. These words you hear are not my own; they belong to the Father who sent me.
John 15
10If you keep my commands, you will remain in my love, just as I have kept my Father’s commands and remain in his love.