If the opposing team partners get the bid, then you and your partner try to set them. You want to put count on tricks you and your partner take. In this regard, knowing what to do comes with experience and playing the odds on domino distribution. It helps to keep track of which dominos have been played and which ones are still held. Sometimes luck and guesswork determine the outcome of a hand.
Doubles are a suit of their own.
If a double is led, then doubles have to be played by the opposition if they have any. If, however, he takes one trick, the hand is ended, and the opposition partners get what he bid. The partner of the high bidder normally gathers in the dominos at the end of each trick they take. The opposing partner team gathers their own tricks taken and keeps them separate from the other team's. The tricks are stored face up, off to the side of the playing surface.