There are two ways to block off times in your calendar.
To can set unavailability from your Dashboard by implementing the following steps:
On the right side of your Dashboard, find the toggle tab and switch it to Calendar View. You will now be able to view your calendar on your Dashboard.
Find and select the particular day you want to register your unavailability. In the popup that appears, fill in additional details and click Add unavailability.
You can also register your unavailability directly from your calendar by following the following steps:
Under Availability, click on Calendars, then select the arrow sign below to view your calendar.
Find and select the particular day you want to register your unavailability. In the popup that appears, select the out of office tab and fill in the details.
NB: The calendar approach allows you to create a weekly/monthly/annual setting.
Click Save to apply.