I need to integrate a payment system with our Windows-based POS system, which we developed ourselves. The integration is primarily for payment and refund operations. Our system is written in C++. How should I choose the integration method? Based on the documentation, should I use the "SEMI-INTEGRATE WITH REST PAY" method?
If I choose this method, I have already created an app in the sandbox environment, selecting the type as "Flex 3," and have also done a preview in the app market. What should I do next?
