How does the code flow in a crypter? What do they do? C# .NE

Question

Okay so..
I've always been interested in crypters because I find it very fascinating.. How it can take a file, encrypt it, you compile it and then when you start the compiled exe it decrypts itself and shoots itself into a memory process..

Atleast thats how I think they work.

Now.. I've been really wanting to learn how to create one but there are so few documents.. Especially when it comes to C#.

And before people start thinking this is for some malicious use. Its not..
If I wanted to use it for something malicious I would have asked how to make a FUD one and no thats not the case..

I would just like to create a SUPER basic one to understand how the code flows.

And when I say SUPER basic I really mean SUPER basic..
Im talking about a WinForm application with a 2x textboxes.. One for the payload and one for the icon and a button that compiles it into a exe.

Are there any documents on this online or is anyone here willing to dumb the process down for me?

Any help is very appriciated.