Within the Diary, you block out times you would like to not having patient bookings. You can do this by going to Diary -> Add Block from the top right hand corner -> Fill in the details of your block -> OK
If you have multiple locations, you will need to ensure you are block this for either one location or ALL if you are unavailable at all locations at this time.
The second way to create blocks is to right click into a practitioner column -> Create Block Here. This training video will step you through how to create, click here.