The general Calendar settings are located under the Settings menu in the Calendar module.
Here you'll find the following settings:
Show absences from the work plan in the calendar: A setting to choose if you want to see absences in the calendar view.
Notify mobile users before appointments and calls: A setting to enabled notifications for appointments and calls.
All appointments for a day can be saved and retrieved, if selected: Allows days to be saved
Which adresse should be used for appointments that are marked as taking place 'Here': When setting a calendar appointment to 'Here', you can here select which CRM object that this should refer to.
View options: Here you can enable and disable different calendar view-options, that are found under the Calendar menu in the Calendar module.