These people will usually get together first. Nonetheless, all members are new to this particular group. If the group is to be successful and complete its task, it must begin to establish itself. Someone becomes apparent as a potential leader if one has not been designated. However it happens, the group gradually establishes its purpose.
Roles become explicit by definition or inference.
In White Stag, we do not leave this important process to chance. He then probably steps back to the cool shade of a tree to see what develop. The patrol counselor watches and evaluates. Perhaps the counselor suddenly interrupts the group on its hike, testing them on their ability to respond to a simulated first aid emergency. Later the counselor sits down with the group and guides them in a discussion of what they have experienced thus far.