Integrating + tutoring a custom Payment Gateway on a premium wordpress theme

Hello, Basically, we're trying to integrate a custom payment gateway ([login to view URL]) into a premium wordpress theme, due to the fact that we're not developers we got stuck! This should not be more than a couple of hours job we hope. The theme developers provided us with a sample gateway plug-in files, and from the other end (the payment gateway) we have almost everything we need (Merchant ID, secret key, API sample codes, express checkout sample codes, [login to view URL] account, etc..). At this point, we need someone to guide us through how the integration process is done for : - API Integration. - Express checkout integration. And no, we're not asking for someone to teach us PHP or anything, simply we just need to see how it's done via Team Viewer on our local server (WAMP) or even a live server. Attached you'll find : - Payment gateway plug-in from the developers of the theme. (Zip) - Sample API integration codes from the payment gateway providers. (Zip, PDF) - Sample express checkout codes from the payment gateway providers. (PDF) Thanks, Adnan M.