In the early days of Pokémon, you could only ever carry six Pokémon at once. Any additional ones caught went straight to your Pokémon Box, which was only accessible via the PCs located in Pokémon Centers. While you can still only have six Pokémon in your party at any given time in Pokémon Brilliant Diamond and Shining Pearl, one way the Generation IV remakes differ from their inspirations is that you can now access your Pokémon Box from virtually anywhere, allowing you to mix up your party whenever you feel like it. However, you won’t be able to do so right away.
To unlock the Box Link feature, you’ll first have to earn the Coal Badge by defeating Oreburgh City’s gym leader, Roark. Your next objective will be to head back to Jubilife City, where you will encounter Professor Rowan and Dawn, who are being accosted by two Team Galactic Grunts. After defeating them, the systems administrator of the Pokémon Boxes, Bebe, will then approach you and link your boxes, allowing you to access your Pokémon Boxes from anywhere.
From this point on, you don’t have to visit a Pokémon Center to access your excess Pokémon. Simply bring up the menu with the “X” button, select “Pokémon,” and then hit “R” while viewing your Pokémon to access your boxes. With this feature, you can customize your party’s lineup at any time, which can prove particularly useful if you’re having trouble with a gym or an otherwise difficult opponent.
