How do I restrict a company level user from accessing specific organisation units?

How do I restrict a company level user from accessing specific organisation units?

The User Org. Unit Permissions screen allows you to specify which employees the user will have access to on Organisation Unit or Region level.

      Navigate > Configuration > Security > Security > User Org. Unit Permissions

Step 1: Select a user.

      

Step 2: Enable the organisation unit checkboxes to which the user should have access.

Important! 
If none of the organisation units are ticked the user will have access to all organisation units. However, if there are organisation units ticked, the user will
only have access to those selected few.