First, you have to buy a desired amount of team account licenses. You can find more information here.
Navigate to the
Team accounts tab and click the
Add Team Member button.
Enter the e-mail address of the team member you want to add.
The new account will appear in your
Managed accounts list. The account is marked with a red circle, because it hasn't been activated yet.
The user will get an invitation link which takes them to an account creation page. A green circle will signal that the user has activated their account. You will now be able grant resources to that account.