A STT is a Single Table Tournament. Here's how they work. A single table tournament takes place on one table of nine players. Unlike multi-table tournaments, which have a scheduled start time and registration period, single table tournaments are "fill and go" games. There's no hanging about; as soon as nine people have sat down at the table, play begins, and once a game has started, another table at those levels opens for registration.
As in any tournament, each player pays the buy-in fee and receives an equal number of chips. Play then starts and continues until one player has won all the available chips at the table. The prize pool is divided between the top 3 finishers, with the winner taking 50% of the prize pool, second place taking 30% and third taking the final 20%
