How to catch your first Pokémon
As with all Pokémon games, when a trainer begins their first journey, they're given a choice of which Pokémon to start with. After you've finished customizing your avatar, three Pokémon will appear in front of you. You can choose from Bulbasaur, Charmander, or Squirtle; after capturing one, the other two will disappear.
But wait: There's more. If you walk away from the original three four times, you'll get a fourth starter Pokémon option: Pikachu.