Here, you can define different types of User roles that you can then allocate to your Users within your systems. Each User can have a different mix of functionalities within the system. If you do not enable User Groups, each User will have full access to all areas of the system.

A User Group can be added, edited, and deleted using the icon shown at the beginning of System Settings.
User Group -  Enter the name of the User Group here, e.g. Finance Staff.
You will then need to add functions to the User Group. You can do this by clicking on the Area to expand and see it's available functions. Once expanded you can then enable Read Access or Write Access.
Note  - if you have User Groups set up and one person is allocated a User Group then all admin staff must be allocated a User Group otherwise they will not be able to enter the system.