I want to know how to iv train
you cant IV train. you just need enough stones to make it perfect. if you mean EV train, there is an ev training location guide here
You can’t IV train but you can breed pokémon to “engineer” the perfect IV pokémon you’re looking for (if the pokémon you’re trying to improve can breed in the first place) without using any IV stone.
…but IV stones are easier and faster.