These settings can be changed via Settings > System Defaults.
Select the "Calendar" tab at the top left.
Your calendar will automatically update with any of the changes you have made after you click "Save".
Your calendar default values will be used on appointment-relevant areas of the system.
Calendar / Appointments
Calendar AutoLock: when creating new appointments, you can automatically lock them on the calendar (so that they can't be edited directly).
Default Timeslot Status: When dragging an unscheduled appointment from the sidebar into the calendar, you can determine the status of the appointment as either "Scheduled" or "Unconfirmed" (needs confirming with the client)
Delete Old Unscheduled Appointments: You may set a timeframe to automatically delete old unscheduled appointments from the calendar X months after its estimated date.
Allocation of Appointment Colour: When creating new appointments, you can change how the appointment colour is determined. It may inherit the colour from either the appointment type, staff, or none at all (requires you to manually change the colour).
If you operate your business in multiple timezones / states, you may toggle on/off the option of selecting a timezone for your appointments.
You may also always show timezone details regardless of your appointment locations.
For example, if your company is based in Australia/Sydney, but you also do jobs in Australia/Brisbane, you can always show indicators for "AEST" and "AEDT".
Change your company business hours and day availability.
Only Display Business Hours: By ticking this option, the calendar will hide appointments which fall outside your company business hours and available days (as selected above).
You may alter the colours for each of the system appointment colours by clicking on the status and selecting a new colour.