Hey Mike I've worked in some prisons, and in the court system. You may not get sent to a high offenders prison, it depends on what you have done, but the ones I worked in were for the very worse offenders. They are very strictly controlled with lots of rules, and the potential for riots and unrest is always at the forefront. Any transgression/s, even if a prisoner doesn't think he is doing anything wrong, is dealt with immediately & swiftly. Even we as staff members were subject to random searches, even before and after we finished work, so everyone feels like they are in prison after a while.
In most prisons there are Chaplains and study groups you can join, so you would not be alone.
I'd say in general keep away from other sinful people, be polite and follow all of the rules, even if you don't agree with them. Don't get caught up in other offenders schemes, or using bad language (using bad language becomes a habit that is hard to break), and try not to socialise with non-believers (might be hard I know). Be polite to others, but distant. Take up study etc to distract your mind, and really, see possible incarceration as an opportunity to study the Word of God (instead of just a prison sentence). Really ponder the Bible and what it has to teach you. Maybe they will have a Bible study group? Keep your mind distracted with healthy things. Write a journal, exercise when possible, eat well and sleep well, as much as you can. Pray like you have never prayed before and believe me, you will get stronger spiritually and mentally. Guard your heart against those who try to pull you into evil, and also guard your mental health too. Use the doctors and nurses there or counsellors, for any mental health & physical problems, and let them know what is going on so they can help you. Try to build up good relationships with those who can put in a good word for you at the end of the day. Stay out of trouble.
I don't know what you did, but I hope that you have seen the error of your ways, and unfortunately, we must pay for what we have done sometimes.
But it's good you have reached out to us for help - kudos to you!
You're on the right path now matey