In the Admin section, there is a menu item available on the left side of the screen named Members. Accessing Members will show you the User / Member Management list. 



From here, you can click Add / Invite Member to start adding a new member. Enter their first name, last name and email address in the relevant fields. Next, choose the roll for the new member from the Role dropdown menu.



Finally, press the Submit button to confirm and add the new member.