There are two ways to block off times in your calendar.
The easiest way is to synchronize your Google or Microsoft Calendar once in your dashboard. Then, simply block off your unavailabilities on your own Google or Microsoft calendar (add events or block off full days). This will then reflect on your MeetFox availability. Make sure your Google/Outlook calendar meetings are set to busy. Refer to this article below on how to do so.
Another option is to go to your "Calendar" in your dashboard. By clicking the respective date, a pop-up will open to add your unavailabilities (certain hours or full days/weeks). Feel free to add as many as you like.