PS4 Controller use in a Unity 3D Project using C# Scripts

Write for me a PS4 Controller integration project for Unity 3D. Make a class with an interface and setup all PS4 Controller functions. It is a standalone project for demonstration. I want to understand in any detail so use comments, heavily. For displaying Buttons and Axis in Unity GUI, simply use a free asset. Later I want to use your code and integrate it into production code. Take your time to write good code. But don't be afraid, we figure anything out together.