01) Access the Control Panel
02) After login click Setup> Credit card plots
03) Define the number of installments with or without interest
If you are interested in setting up interest payments, you need to install the module of additional payment rate and number of installments
01) In the Control Panel> Modules> Orders> Additional fee by payment type and number of installments> Click the Install button
02) Set the additional interest percentage in the Surcharge Percentage field
03) Set the name of the payment module in the Payment Type field