Tuckman's stages of group development

The Forming – Storming – Norming – Performing model of group development was first proposed by Bruce Tuckman in 1965, who maintained that these phases are all necessary and inevitable in order for the team to grow, to face up to challenges, to tackle problems, to find solutions, to plan work, and to deliver results. This model has become the basis for subsequent models.

https://www.youtube.com/watch?v=2AXOSQT5yVQ