You can join a bingo club from the main menu of the game, after you reach level 8. To join an open club simply Click the Find a Club button in the main Lobby and select the Club you’d like to join from the list displayed.

If you want to create a club, you'll need to name your Club and then set the permissions.

An "Open" Club means that any user can search and join. "Invite" means that you have to send them an invite, and "Closed" means that the club cannot be joined by any other members