You can add a new user from within the Practice Admin section of the system.  This is the bottom icon on the main navigation section denoted with the cog.  It is only visible to those with admin access.

From the Users tab in the Practice Admin section click on the +Add User button.

Now complete the fields required to add a new user.  If you try adding a user and their email address is already present in Hindsight you will not be able to add them again.  There are 3 practice level roles to choose from.  These determine your access to system level features.  Access to clients can be added when assigning client level user roles.

When you click save Hindsight will automatically send an email to the new user for them to activate their account.  If they do not activate their account they will not be able to access Hindsight.  If they do not receive the activation please check junk/spam first.  You can re-send an invite from within the user profile on the User screen by selecting the edit option.