In STOA Apologetics, there are 6 categories. Each of these categories has 3 different types of questions.
At a tournament, you will compete in 3 Apologetics rounds. Each round will have questions from 1 category. You will draw at random (probably through slips of paper) and receive several options for which question you want to answer. For example, you may receive 3 options from category 3. "What does the resurrection of the body mean? Why does this matter?", "Did a loving God create Hell?", and "Why am I here?"
NOTE: While in a round at a normal qualifying tournament, you will receive questions from the same CATEGORY. That does not mean they'll all be the same KIND of question. You may get 3 definition questions. Or maybe 2 general questions and 1 statement analysis question. But they'll all be from the same category.
For preparing cards, there are many different theories on how to bet prepare for Apologetics. I usually just take one card at a time, and take as much time as I need. For me, Apologetics is about learning what I believe and why, not winning tournaments. I actually am opposed to using Apologetics as a competition.
But that's another story. Regardless, I'd encourage you to dig as deep as you can, focusing more on learning than anything. Take your time. Very few competitors ever have cards for all 106 questions.
Another popular method for preparation is preparing general cards. Some competitors will make cards with verses or verse references dealing with certain topics. Usually, this is a technique used by more advanced speakers who are more comfortable making impromptu speeches.
I'm not sure what you mean by "what is everything else on that document," because it seems to mostly just be the questions. The elements/principles part is about how they want you to conduct yourself (Honoring God, always being prepared, being gentle...)
As for the other two documents...
The rules are simply the rules of the event. Every event has them. It will have a lot of similarities with other events' rules. Are there any rules that you don't understand or don't understand why they're there?
As for the student ballot, that's the ballot that the judges will use to provide you with feedback. As you can see, there are boxes for them to check/x to signify if you did certain things (demonstrating why the topic matters, having a clear conclusion, having cards) as well as a place at the bottom where it will inform you of your place in the room according to that judge (1st place, 2nd place, 3rd place etc.) Below the placing, there's a blank space for feedback, so you can learn how to improve for the next tournament.
Hope that helps.