Help with creating a weapon?

[Uglulyx]

How do I add a custom texture to a weapon?

 

I want to make a unique version of the vanilla assault rifle with a unique texture and sounds but I don't know how :( I have all the textures and sounds already just need to find a way to add them without replacing them for every assault rifle. I have fiddled with it a bit and cannot find anyway to do it. And there are no tutorials for it anywhere!

 

On a side note. Does anyone know how to allow multiple textures for raiders? I am making a tattoo mod and I think it'd be nice to have more than one set for each sex so it doesn't get repetitive.