The Fifty50 is a single table SnG tournament. If you use Prize Distribution = Fifty50 scheme, the tournament will be stopped when half of the players are eliminated. The remaining half of the tournament participants get paid according to a special formula. It implies that half of the prize pool will be paid to the winners in equal parts. In other words, everyone will get a buy-in excluding rake payout. The second half of the prize pool will be distributed among these winning players depending on the size of the chip stack left. Thus, a finisher with a bigger stack will get paid more than someone with a smaller stack.
The Double Or Nothing tournament is a single table Sit&Go tournament. If you use Prize Distribution = DoubleOrNothing scheme, the tournament will be stopped when half of the players are eliminated. The remaining half of the tournament players will share the prize pool in equal parts, i.e. every player is paid a double buy-in amount.
The DoubleOrNothing scheme is only available for Sit&Go tournaments with even number of players.
Rapid tournaments work according to the same principle as Fast Fold tables: the moment the player presses Fast fold button at the table, they are seated at another table to start a new hand. The players randomly move on each hand. The player with least count of posted big blinds among all other players at the table posts a big blind.