How do I delete and add pokemons for my team?

If you want to add a pokemon to your party, you must do one of the following.
1.Catch the pokemon you want with a open space in your party of 6. The captured pokemon will be placed in the next open slot in your party.
2.If your party is full, go to the nearest Pokemon Center and interact with the pc to the right. From there, Select Bill's[or someone's] pc, then deposit, then select the pokemon you wish to switch out for the one you want.
After doing this, go back to the Bill's pc menu and select withdraw.
Then select the pokemon you want in your party, and it will be in your party!
If the box is full and you can't deposit a pokemon, just change the box to a unused box, then deposit the pokemon.(Recommended)