its hard to believe that you really did read any tutorial, because they are like STEP by STEP explanations.
Well, maybe you explain a bit better, where exactly the problem is?.
YOu got it in the Import Manager, so now you only have to change the name of the skin into that name, the creator of the model wrote somewhere.
Thats how it looks, when u import:
wc3imported\"Name".blp
and thats how it could look like:
Textures\"Name".blp
Then you just save the map, and then u can use the model in the object editor.
Sometimes you have to close the map and reopen it, so yeah... thats it....
Greets