There are many complexities when dealing with card transactions. If you try and tackle them all at once the task of integrating will seem complicated. The best way to do the integration is to follow a simple step by step approach and break the process down into manageable sections, each adding functionality as you go along.

To assist you example code is available in the resource section in most of the common programming languages. Where possible please use these well documented examples as a starting point.

Adhering to good coding practices will also greatly simplify your task.