Everything is better with friends, and that applies to Pokemon Brilliant Diamond and Shining Pearl. If you want to play with your friends, battle together, and generally enjoy the games, there are a few things you will need to know.
First, you will need a Nintendo Switch Online membership to play the game online and access all those features. Battles with other trainers, trading, and all that good stuff will require the online membership.
After that, you will need to make your way to any Pokémon center and head down the red escalator. This will bring you to the Union Room. Speak to the people behind the counter and they will tell you that you are in the Pokémon Global Club.
They will ask you if you want to enter and give you four options:
- Yes, with my group
- Yes, with a Link Code
- No, thanks
Pick the option that suits you the best and then you will be able to enter the Global Room. If you pick a Link code, just give it to your friends and they can use it to gain entry and will be able to battle and trade with you.
Keep in mind that for trades, you will need to have completed the first gym before you will be allowed trade with other players.