When a customer submits a booking request, they mean business. They're ready to book.
To submit a booking request, the customer has already viewed your profile, checked your function PDFs, met the capacity requirements and selected a space for day that's available (as set by you) and met the minimum spends for that date (again, as set by you).
Basically, they're keen.
The process from here? Send a quote, they accept (or reject), it gets booked, a deposit is paid. Simple!