@Albert10 A confirmation code, also known as a reservation code, is code associated with a confirmed reservation. Yes, a reservation can only be confirmed if the guest has paid. Once a reservation is confirmed, the dates associated with that reservation are blocked on your calendar so no one else can request a reservation for those dates. Here's an example of what it looks like:
In my case I blocked off May 16 & 17 for personal reasons and I have my availability settings set to allow one day before and one day after a reservation for prep and cleaning time.
Hope this answers your question!