Booking slots may not appear on the booking page because:
The time slot is not added.
You have not added the PAX, it means a number of people who can book an appointment in that particular slot.
To CHECK:
Go to the "Category".
Click on the "Calendar" option under "Action".
3. Select the date you want to check. Select "Edit date or edit all days".
4. You can check the time slots and PAX.
5. Click on "Apply".