1. Your character age must be 11-18. I might let in a 10-year old, but 11 seems more likely.
2. Your Pokémon party may consist of 3 Pokémon maximun when you start out.
3. You are allowed 3 Basic or Baby Pokémon (Eevee, Absol, Plusle, Elekid, etc. along those lines) in your beginning party of 3. You are ONLY allowed those three at the beginning, then, as you advance you will be allowed to have more Pokémon in your party, and evolve them as well.
4. You may pick ANY Pokémon to start on your team except for legendaries (Mew, Lugia, Groudon, etc.), and semi-legends (Arcanine, Lucario, etc.), although you CAN start with their PRE-evolved form, and work your way up. (Example: Start with Growlithe and evolve it later)
5. The Trainer Points are what cause you to level up in Trainer Level.
The higher your level, the more Pokémon you can have in your Party.
You gain experience points by winning battles, helping out, and doing various other things.
You CAN lose experience points through various ways, such at bad behavior, being a sore loser, breaking the rules, or any other thing that you can think of that would cause damage to the school and it's students.
6. RESPECT. YOUR. TEACHERS. No beating up on them because they started with higher Pokémon than you, no deliberately ignoring them when they want to speak to you, and most of all, NO dissing. Keep your cool people!