From the Introduction:
Dead Ringers is a role-playing game for 3-5 players (probably best with four players). If you are reading this, it is likely that you know what a role-playing game is. There is no Game Master for this game and it is designed to be played in a single session as a one-shot.
The game will be played in four "rounds" with each player setting up one scene for each round. With four players, that will be a total of sixteen scenes. Some players will be humans and some will be ghosts, though no one will know who is who. At the end of the game, one of the sides will win.