If you take payment from your customer alternative payment methods such as cash, bank transfer etc you will need to allocate this money to your booking(s), to track revenue and a customers outstanding balance.
If a customer is paying for a single or multiple bookings as once there are a few options available to you.
Directly to the Bookings
Open the customers profile and click into the unpaid booking(s), if the customer has multiple unpaid bookings you will see any unpaid bookings from customers History Screen (the link for this is in the left hand menu).
Once you click into a booking, you can enter in the payment record form the Payments panel on the right hand side of the screen.
Allocate Total to Multiple Bookings
If you click into the customer profile from the left hand menu if you click on the 'Apply Payments' link.
From this screen you will see and bookings with an outstanding balances, from the right hand enter in the amount of money paid by the client and then click 'Apply Payments', the system will then create payment records for each booking (in order of the oldest booking first).
If the customer has not paid the full balance, any booking that are not fully paid will remain unpaid until the balance is fully paid.