The BookIt plugin also has the section called calendar (follow BookIt Calendar > Calendar).
On this page, you can navigate the actual calendar and look through all the appointments.
You can apply filters to display arrangements by service or by staff. Select the service or staff you want to see the booking.
The days on the calendar with the bookings are marked with small dots in the right corner. The Yellow dots mean that the appointments for this day have pending status and must be approved or rejected by the admin. The Green dots indicate that there are approved or rejected appointments for that day.
To see the details of the appointment click on that day. You will be able to Approve or Reject the booking.