Cooperative play takes place between two or more children. In cooperative play, children exchange ideas about the game or the toy they are playing with. Children generally have clearly identified roles in the play, but these roles can change throughout the game. Play may last only a few minutes or it may stretch out for longer periods of time.
In order to be successful in cooperative play, children need to have developed certain social skills. The first skill that they will need is the ability to enter a play situation appropriately. Young children may want to join a game or activity, but not know how. Imagine that 3-year-old Michael sees other children building with blocks. Michael wants to build with the children, but he hasn't developed the ability to verbally ask to play. Instead, he runs up to the block structure and knocks it down. Teachers can help children develop the ability to appropriately enter play by modeling how to do this. For example, after Michael knocks down the blocks a teacher could calmly say, "Michael, your friends are sad because you knocked down their blocks. Did you want to play with them? "Michael nods. The teacher says, "Try saying, 'Can I play with you?'" ...
In this answer I explain what cooperative play is. I also list several social skills that are needed before young children are able to play cooperatively and I give examples to help you understand how these skills might look in a real preschool classroom.