A supervisor or unit manager gets visibility in the individual employee's work calendar when he is marked as the employee's supervisor. This is done in the Employees section by opening the employee's information and selecting the desired supervisor from the Supervisors menu.
If you want to give the unit manager visibility into the calendar of several employees at once, you can do this by marking him as a deputy for all supervisors in the unit. You can also assign a deputy for the unit manager/supervisor. The deputy gets the same visibility in the employees' work time calendars as the person being substituted has. In this way, the unit manager can see the information of all the persons who are marked as subordinates to the Supervisors and he does not have to be marked as the supervisor individually for each employee.
You can define the deputy in the Employees section by opening the information of the desired supervisor and then the Deputy tab. Search for the desired substitute (unit manager) in the Deputy field by name.
Visibility to the subordinates' work time calendars is always defined for a limited time since you need to choose also the start and end time for the deputy role. Save the changes with the Save button.
More information about assigning a deputy can be found here.