The Bookings report counts the diary itself. Find it under Reports in the sidebar (owners and managers).
Pick a date range and you'll see how many bookings were made for it, how many completed, how many were cancelled or missed, and the share booked online - customers booking themselves on your page or website rather than entered manually. Each figure is compared against the period of the same length before it, a chart shows the diary day by day, and a busiest-times grid shows which weekdays and hours your bookings actually start - darker means busier, and it's the picture to roster from.
The online share is worth watching: every percentage point that moves to your booking page is time back for you.
Bookings imported from your old system are counted on their own, and the online share leaves them out, since nobody made them here.
Export CSV downloads the day-by-day table for the range on screen. For what missed visits cost you, see the No-shows & protection report.