Navigate to Money > Bank accounts.
Scroll to the bottom of the screen and click on the Explain link beside the appropriate bank statement to begin explaining.
Click on the appropriate payment amount within the table of transactions to explain.
Select the appropriate supplier in the To box.
A table with recent bills for the customer will now appear. Use the box in the To pay off column to enter how much of the payment to allocate to a particular bill. By default, this will be the full amount.
Click on the Add transaction button to allocate the payment to the bill.