If you registered for the Ultra Sinnoh Classic Online Competition and completed at least one match, you can now claim your participation prize of 50 Battle Points. Just log in to the PGL using the game you used to participate in the Ultra Sinnoh Classic Online Competition, and then click here. To redeem the code in your game, select Mystery Gift from the main menu, then select Receive Gift, and then select Get with Code/Password and follow the prompts to enter your special code. Be sure to enter the code in your Pokémon Ultra Sun or Pokémon Ultra Moon game before April 30, 2018, at 23:59 UTC.
Visit the Online Competitions page for Ultra Sinnoh Classic Online Competition player and Pokémon rankings.
Source: Pokémon Global Link