I'm gonna sound really stupid, but...

[Gutrot The Legend]

How do you put a new skin onto a model?

 

[ultra.x]

It depends what the skin is of, you must put the skin into the importer and give it the path needed. If you dont know just show me the skin and where did you get it from.

 

[Lich Prince]

Ok. Open your editor, go to import manager and import your downloaded skin. Enter the CORRECT path. Now save-close editor and reopen the same map.