In the competency settings, you can specify which employees can perform a certain service.
Set competency for a service
In the "Competencies" menu item, you will find an overview of all employees and their roles. Select the employees or roles to whom this service can be assigned in the calendar.
Example of competency settings:

Set competency in the competency matrix
In the header area of your service overview, you will find the "Competencies" tab, which shows you a clear view of all your services and the employees assigned to each:
