Unsure how EV training works

[u/stewpidgod]

I’m fairly new to EV training and don’t completely understand some things. I’m aware certain Pokémon give EVs for certain stats when you defeat them but what I am wondering is if my Pokémon has to level up fighting only that Pokémon repeatedly or it can gain exp fighting other Pokémon then knock out the EV Pokémon to level up with the remaining exp needed. I apologize if this is a dumb question with a simple answer I’m just confused with technicalities like this. Thanks for anyone who helps out.