If you wish to add an admin to your management dashboard, head over to the "Users" tab, and in the Admins section, click "add admin +."
Enter the user's email address and click "Invite" then "Add."
It is important to note that adding an admin to your dashboard will not automatically give them access to a Business subscription. If you'd like an admin to have that access, you'll need to add them to a user seat.
To remove an admin, click on the "X" button over here: