Quick skinning and/or hexing tutorial?

I’m a real skinning noob and I want to make some skins for myself without them replacing anything.

I saw a personal skinning tutorial but I didn’t really understand it a whole lot. So, I’m looking for a simple, easy-to-understand tutorial. I’m worried I can’t ask for something like that without people freaking out at me.

I have Photoshop and Paint.NET on my computer, but Paint.NET is really the only one that is easy-ish to use for me.

Oh yeah, and I don’t want anything replacing anything.