http://forums.pokefind.co/index.php?threads/faq-questions-and-answers-frequently-ask.47/ Q: How to fight Pokemon A: select your Pokemon in the Hotbar and right click it. Q: How to fight other players A: Player 1 throws out his pokemon. Player 2 throws his pokemon onto player 1’s pokemon. Player 1 then has to click on accept Q: How to increase Trainer Level A: Defeat pokemon in battle
Go to that link I posted. It has these questions listed. Level up Pokémon by fighting wild Pokémon, players or gyms.