Start by heading over to your Settings tab and select Scheduling
Set the number of bookings you will accept per day, as well as how long you'd like each booking to be.
Adjust the amount the number of hours beforehand that a client can book a session and how far out in advance.
Give your self a good amount of time before and after a session to avoid an overwhelming day or overlapped bookings.
Finally, adjust how much flexibility you're allowing your clients to have in terms of canceling and rescheduling their sessions.
Hit Save and you're all set!
Your clients will see this information reflected in the Lead Form that they fill out on your website. You can also keep your calendar availability updated inside the Calendar tab, here's a great walkthrough of how to get that done https://help.bloom.io/en/article/easily-set-up-your-availability-19g47ok/.