The Availability Manager under your Settings menu will allow you to configure what's available for your Clients to book appointments directly into your diary.
You can block out specific times of the day, or days of the week which you do not want to receive direct bookings for.
You can also toggle your Availability Manager to schedule blackout days and holidays in advance. Just flick the dropdown on the top right to 'Holidays'
When your clients come to Add a new Inspection via the InventoryBase Dashboard, they'll only be able to select days and times that aren't blacked out via your Availability calendars.