The first box in the top left corner of the screen will be labelled Payment Type Setup. Here you can view, create, and edit your payment types. You can also select an entry and use the and buttons to rearrange how your payments will display when processing a sale (only the top 12 will be displayed in the full payment window, the rest will appear under "special payment types")
You can add new payment types or edit existing types by using the menu to the right of the payment types.
First enter the name of the payment type you will be creating into the Type Name field, or select an existing type from the list to the left. Key in the exchange rate into the Exchange Rate field (by default this is set to 1). Check the Requires Reference Text box if the payment type you are adding will require a reference (cheque number, for example). Press to save your changes.