It's quite simple!
Choose a game mode using the [Mode Select] button beside the [Play] button on the bottom right corner of the Home screen, then hit [Play] to join a match!

Each match has a capacity of 32 players and consists of up to three rounds. Once the final round draws to a close, the player with the most Rings will be declared the winner!

Each player will receive Rings and XP based on how well they performed, so go out there and do your best!