Taken directly from the siege page
Win as white to capture the board, winning as black will successfully defend the board.
A draw will count as a capture for white, and the defending black player will be ousted.
A queue of challengers will develop - the defender must play each in sequence until beaten.
The defender or the new challenger may start the next waiting game at anytime.
You may only be in one queue for each timeout series, although you may be at a board and waiting in a different queue.
Dominate this game by achieving consecutive successful defences.
Win and you keep playing at that board, lose and your gone.