You can block the dates/hours by visiting your single listing page (e.g. if just one of your studios is not available that day) and click on Calendar. Please keep in mind that every calendar displayed on each of your listing pages is independent from the others.
If you want to see your active bookings all in the same calendar you can click on Calendar in your User Menu (click on your username to see it).
On each listing page you can find a weekly calendar with days/times. Select a time slot (tap on it on mobile).
When selected the time slot will turn blue. Click on the Lock icon to lock that specific time slot. To unlock it, select it again and click on the Unlock icon. You can repeat this process as many times as you want. A blocked slot will turn pink.
You can also customize the shade of pink by tapping multiple times on the Lock icon if you need it. The different shade of pink won't affect the blocked time, it's just aesthetic and can be used as a personal reference for you and your staff.
E.g. You may need to use "light pink" meaning "Studio closed" or "dark pink" meaning "studio already in use".
Your Guests won't be able to see your listings' calendar but each calendar will affect your Guests' bookings. This means that if you block "Monday, May 8th, from 1pm to 2pm", your Guests won't be able to select that day and time slot when booking.
Anyway, in case of doubt, they can message you for asking specific availabilities whenever they want (there's a Message button on each of your listings).