The player to the left of the shuffler begins the bidding. If all players pass, then the shuffler must take the bid for at least 30 points. Each hand won is scored as a mark. The partner team who score seven marks first wins the game. This is done by playing a domino with the high end equal to one end of a held double when the player cannot follow suit in a trick.
Trumps are like a suit in cards.
When a trump is led, each player must play a trump if he has one. High trump wins the trick. If a non-trump domino is led, and a player cannot follow suit, he may play a trump if he has one. The highest trump played always wins any trick. A player may play any domino if he cannot follow suit.