This is about the quickest tutorial I could come with.
If you know how to make a layer you can play around with textures
and see results after saving and viewing in Assetx by clicking the *.im .
You can have Assetx open *.tga in Photoshop.
I have found high rez pictures of locoes and did a copy/ paste of weathering the fade the layer
so the details show thru.
Experiment make a mess have fun..remember your not going to get right the 1st time.
Almost forgot..CLONE....
Gerry