The four stages of group building are forming, storming, norming, and performing.
Forming happens when the group or team meets and first comes together. This is the beginning of the team.
Storming happens when people begin to figure out where they fit into the group. Some people like to be leaders, while others are happy working in other ways.
Norming is the time when things start to get easier and rules are formed. People have accepted their roles on the team and everyone is starting to work together to create group cohesion.
Performing is when the group or team finally hits their stride and works together to accomplish something.
Sorry if I'm late!