To play Pokémon: Let’s Go! with a Poké Ball Plus as your primary controller, you must first connect it to your Switch. (This is thankfully a much simpler process than hooking it up to your phone, which we’ll get into later.)
The first step is to make sure your Poké Ball Plus is charged. Once that’s done, you’ll have to connect it to your game. Open up Pokémon: Let’s Go! and head into the Options menu.
Nintendo via Polygon
Once there, navigate to the “Open controller settings” menu. The game will present you with four different controller options: left Joy-Con, right Joy-Con, the two Joy-Con together and the Poké Ball Plus.
Press in the control stick on the Poké Ball Plus (the white one that juts out) to pair it with the Switch. Make sure that Bluetooth is on! If you’re successful, it will light up on-screen.