I maybe wrong about this, so please forgive me if this is not accurate.
The number of teams will be determined by the number of people that want to play. To my knowledge there has been no limit set on number of teams.
If a team that is ready established needs another player for some reason a team captain might pm you and invite you to join them. (This is how I started with it)
Old Gobbler will start a random team entry thread in a month or so. Anyone that wishes to play and is not already on a team will sign up there. The site will then assign you to a team needing players or will start a new team as need to accommodate everybody that wants to participate.