"Fairly new to the game. Question about taking over a gym."

#PokemonGO: The gyms in my town appear to have fairly weak Pokémon guarding them. For example 1 gym “yellow team, I’m red” has a CP level 441, 470, and 419 guarding it. I’ve got a 1413 Vaporeon, 1012 Tauros, 1001 Magmar. Can I use all of these to help take over or will only 1 Pokémon fight all of these? I could turn this into multiple question I suppose but could one of the veterans give your feedback on this? I didn’t want to walk into this gym blind not having a clue how it actually worked.Thank you in advance! via /r/pokemongo https://ift.tt/2Tob11k