How can I prepare or AIT as a 42A (Fort Jackson)?

If you google the six weeks ACFT program, you can adjust your program to your timeframe. I would recommend you not to be a couch potato. Also, continue to read over any materials that you have from BCT. Basic Soldier skills are perishable.

Just finished AIT about a month ago. School in AIT isn't difficult. Mostly consists of following along and using CTRL + F to search for information in regulations. Heads up about notes. You can take notes in the school house but you wont be allowed to take them back to the barracks. All tests are open note and you can use the regulation to find answers. Notes used during the test will be turned in once the test is complete and they will shred them. Even at the end of AIT you will have to turn in your notes. You will either be in B, C, or D Company while there. Hopefully you end up in Bravo since they have some amazing Drill Sergeants that will help you with just about anything and they will push you to be better. Memorize the AG Creed. Keep in shape because you will take the ACFT while there but also practice for the APFT because your unit may still that test.

You can also search YouTube for short videos of how to properly perform PRT exercises. Many of us used these videos while in Advanced Leaders Course (ALC).

Keep up your good motivation. When you go to AIT, the subject matter is not difficult, but there is a lot of information that you WILL use when you get to your first unit and start working in the S-1 shop, so take good notes and pay attention.