[SOLVED!]Creating/Adding more skins to a model..?

[BrokenTripod]

Well, I'm attempting to make a map and I'm trying to make it so there's a model and the skin changes to another skin. By default, the model only has a single skin, and I'm trying to give it another, custom one, that I made.

I was wondering if there were any tutorials on this, as the only ones I can find go over how to replace skins, not add a separate one.

Any help is appreciated!

EDIT: It's a valve model, by the way

EDIT2: Oh, I found a tutorial in the modeling section of Interlopers. That was dumb! Anyway, I'm done here. Just copy the model instead of trying to figure out how to add skins. It works and it's simple. Yay.