Do bookings change your calendar availability?

Hi, I have many dog boarding requests for August, none of which are confirmed yet, but a lot that will be confirmed closer to the dates. However, i've gotten other requests for bookings on some of the same days which i've had to turn down due to only being able to house one dog at a time. If I book these requests now, will my calendar change my dog boarding availability to 0 or will nothing change? If yes, I will want to book my requests asap so other clients know that I cannot board their dog. Thanks in advance