Instructions
Enter a Pokémon Center in any major town.
Access the PC to the left of the healing desk on the first floor. Select "Amanita's PC."
Choose "Deposit Pokémon" to put a Pokémon from your bag into storage. Select a Pokemon, choose "Deposit" and select a storage box for the Pokémon. Use the "L" and "R" buttons to scroll through the storage boxes. Press the "B" button and then select "No" to return to the PC's main screen.
Select "Withdraw Pokémon" to take a Pokémon out of storage. Choose a Pokémon and select "Withdraw" if you have an empty space in your bag. Press "B" and choose "No" to go back.
Select "Withdraw Pokémon" or "Move Pokémon" to get rid of a wild Poké. Choose a Pokémon and select "Release." Choose "Yes" to confirm your decision.