Custom user menu can be selected from the list and allocated to the role through the 'Manage Roles/OUs'  page under System Admin module.

System Admin -> Rights Management -> Manage Roles/OUs

When the users of corresponding role login the application, user will be able to view only the corresponding modules defined in the allocated user menu.
This helps to ensure access on unauthorized modules and forms.

Click below link to view create Manage Roles/OUs Video: