Clicking this menu item leads to a calendar. Days that are painted yellow already have special timeslots assigned.
Selecting a day, the user gets a timeslot overview for that day. The timeslots for this day can now be changed, e.g. for creating an event or holidays.
In this case, one timeslots for the court "Badminton Court 1 Indoor" was deleted by clicking the 'x'. It now appears in grey. One new timeslot was added (yellow) for that court. Saving these changes, the new timeslots will appear in the front end for that court.