When a new user signs up to Chain in your practice, an 'Admin' in your practice will have to approve them as part of the team. Until you approve them they will not be able to use the full functionality of Chain.
They will receive a notification on the toolbar that takes them to the 'Practice Users' page, where they can approve new users.
On the 'Practice Users' page you can go to the Unapproved Users, click the button with the three dots to the right of the user and click approve.
If you are an 'Admin' you will have the ability to approve new users, make other users an 'Admin' (also via the 'Practice Users' page) and archive old users that may have left.
If you are not an 'Admin' you will be a 'Member'. You will still be able to use Chain as an 'Admin' would, but you will not be able to approve or archive users. If you wish to be an 'Admin' you can ask another 'Admin' in your practice to make you one.