How to invite a friend to join a team?
Alice goes to team settings:
Alice goes to team settings

Alice invites a member as an administrator:
Alice invites a member as an administrator

Alice invites Bob to join "Art classes":
Alice invites Bob to join Art classes

Bob receives an e-mail to join Alices team:
Bob receives an e-mail to join Alices team

Bob joins "Art Classes" team:
Bob joins Art Classes team

Bob confirms joining the team:
Bob confirms joining the team

Bob can now work with "Art Classes" team:
Bob can now work with Art Classes team