Open the game and tap Join.
On the Make Purchase screen, tap Add promo code (optional).
Enter the code before you pay.
You can use one code per booking, and it works together with your game credits. A code only covers your own spot, so book yourself with the code first, then add friends in a separate booking without a code. Friends who have their own code can book their own spot and use it.
Code not working? It may have expired, not be valid for this game, or have reached its limit. Double-check the characters too, since it's easy to mix up a "0" and an "O" or a "1" and an "I". Some codes also need a verified email address. If it still won't work, message us with the code and the game.