How to record HTTP Traffic like Charles

Question

As I am new in .net and going to create an desktop application, which tracks all web traffic. So i need to know how can we do this? i tried stackoverflow also. and found this.

How to capture http request/response traffic results

But I don't know how to use this in a desktop application?

So please help me out in this. Remember I am new in C# or .net code. I know Oops very well, so can understand the logic.

I have used Charles software and its amazing. I want to create the application like this, for my existing project, but for file comparison.