Steps to add more prosites payment gateways

Stripe does not allow people from my country to signup for an account and I need my clients to be able to use their credit cards to make payments. I can’t use paypal pro to accept credit cards either as that requires me to be resident in the US. There are plugins I can use, such as paystack plugin, to solve my problem. I need to know how to add more payment gateways to the prosite default gateways. I don’t mind editing the codes as I am also a programmer