FusionReactor on-premise's default user model provides 3 user roles:
Administrator
Manager
Observer
These user roles control what features/capabilities a user can access via the user interface.
By default, a login is restricted to these 3 roles. It is also possible for FusionReactor to have individual user logins setup. These can be configured by connecting your X.500/LDAP-compliant Directory Server to FusionReactor. You can read more on configuring this in the documentation.