Within this modal, you will also have the option to decide if you would like to make this user a Team Admin. The only difference between a Team Member and a Team Admin is that Team Admins are able to also manage the members within that team (such as add and removing members). It is important to note that this does not mean team admin members have additional privileges on the Projects that the Team has been assigned, but only applies to permissions to the Team itself. After you click the Submit button, the user will show as added to that team.