Assign bookings to cells based on date ranges of new & existing bookings

I'm making a booking system in excel for a campsite. I've made most of the system, including a layout of the campsite on a sheet, and am trying to make it use this to organise bookings.
-It needs to check the date of the current booking and check through the records of all bookings from the site layout and/or the order history to see which pitches are free.
-It then needs to assign the current booking to a free pitch at that date and record this in both the booking history and the site plan.
The site plan would have to be able to change for each week, to show which pitches are booked in that week.
This probable doesn't make much sense, but I've attached a copy.

Thanks in advance for any help