In order to configure this extension, go to System > Configuration > Multiple payment
You will have this screen :
Custom payment methods : Here you can enter your custom payment methods, this methods will be available when you want to do multiple payment.
Please enter one payment method per line.
This method will NOT be displayed in your cart or checkout screens
Don’t consider orders before : If you don’t want to display old order in pending payment report, enter a date like YYYY-MM-DD.
Example : 1st February 2015 is 2015-02-01