Battling
Battling is reletivly simple. When just two pokemon battle each trainer says what attack they want there pokémon to use, the ref tells them how much damage it will do. There are three types of battling: Set, Shift and Normal.
Set
A set battle is where you and your opponent chooses how many pokémon to use, no more than 6, each of you tell the ref the order and name of each pokémon you will use, once your pokemon is out you cannot change him, the order your pokémon are in and what order they come out.
Shift
A shift battle is where you and your opponent choose the number of pokemon you will use no more than 6, You tell the ref what pokemon you will use and you can change there order any time, Ie, You have squirtle bulbasaur, pidgey and electasbuz, and your squirtle faints, you can send out electabuzz.
Normal
A Normal battle is where you choose a set number of pokemon, you don't tell the ref any of your pokemon except your first one. after it faint you can send out any of your pokemon from your list. but once one is out you cannot call it back like a shift battle.
Masters
Now when two masters fight there pokemon they can fight to help there pokemon themselfs, they get 50 more hp than there pokemon has at the begining of the battle. Masters also can attack each other while battling pokemon. But you cannot attack in the same turn as your pokemon ie, your opponent just went and you want to make a move you can, then your opponent attacks again, then your pokemon can attack. The rest is exactly the same as the above battles.