I have no clue about this game, and you probably already know this but if you don't, it might help:
"When you enter the Battle Tournament, you have the ability to select two Helper Pokémon. Similar to how they would come in a pinch during normal battles, these Pokémon will come in and attack the enemy, doing damage while they go. This is a useful tactic when you the Pokémon is much greater in power and HP to have some back up to knock some out. To activate them, all you have to do is press the A Button at any time. This calls them into battle and they shall quickly attack, do the damage, and then leave. You can only use each backup Pokémon once per round, and you cannot skip one to get to the other one."
Just a suggestion, sorry if this is no use to you whatsoever.