You can use "Away" time to block off one-time, unavailable periods. This will create blocks in your calendar during your “Regular Hours” when you would otherwise be available. This is useful when you need time off or will be unavailable for appointments. Clients cannot book over your "Away" time.

To update your "Away" time, navigate to your Availability tab from the left navigation. Select "Away Time" from the center tabs.

From this page, you can click "Add Away Time" to choose dates and times when you are not available.

Note: these will be one-off blocks, they will not recur on a weekly basis. To edit your Regular Hours, see this article.