The calendar settings allow you to customise your calendar view. This includes setting the time span, times visible, days visible, schedule colours and labels, and the schedule information you would like to see displayed.
Some of the settings you choose will be reflected in any external calendars you choose to subscribe to.
Which Business Units?
The calendar will show all schedules from the current business unit as well as any child business units. The 'Include All Business Units' option will show all schedules from all business units.