[SA] Skinning Help

[Daze]

First of all, If this is in the wrong section, sorry and please move to the appropriate.

I've looked around a lot for tutorials on skinning, found loads helpful but not what I needed

When ever I open the txd I want to edit all I usually have on the original txds is the parts and decals but no body, brakes etc.
I've heard it's something to do with Alpha mapping or something, could someone explain what an Alpha map is and maybe direct me to a site with any information, not really requesting a tutorial just want some infooo  

Cheers  

[Pendji]

attached got no decals

[Daze]

Thanks a lot Bazrun!
I think I know what to do now, bit stuck on how to edit the part where the paint job goes on the originals, help would be appreciated