A club on Spigo means that a small or large group of players come together in a collective. There are no limitation on the number of members in a club. Every member of the club contributes with rating points to the total rating of the club. The contribution counts for all the games in which you play for rating. If you win, you add rating to the club. If you lose, the club will lose rating as well. You can only be member of one club at the time.
Choose "Create club" in the menu to the left to get started.