To integrate your online ordering store with USA ePay, you need to get your Source Key.
Your Source Key is a unique piece of information specifically associated with your payment gateway account through your credit card processor.
1- You'll want to enter this by Settings>Order Payment
2 - Choose USA ePay from the gateway list
3 - Enter your key, check off what card types you want to accept, select the order types that you want to collect tips on & hit Submit at the bottom of the page.
At this time, Orders2me only supports USA ePay console v1 ONLY without PIN.