Skin Confusion

Okay, I have no problem importing skins that have models with them (most of the time) but when it comes to just skins I'm baffled. What I do is just put them in my Warcraft III folder and then import them, it's the only way I can get it to work. However, as I soon realized, this works for all the maps, so each time I want to import a skin I have to give up an already made skin. People tell me to upload it not directly from my wc3 directory, but from places inside it. I don't understand. There is no Units folder in there. Do I have to make the folders myself? I don't get it.

OK this post is quite old, but i'll reply because there are 0 responses. If you didn't get Tft get it. When you load up editor notice the new Module Tab. Click it then drag to Import manager.
Import then skin then double click it, check custom path file. And enter the correct pathfile. Now that skin only apllies to that map.

Everyone Thanks Blizzard for accepted custom Skins, Models, and overall change.

I understand that, but where do I upload the skin from and how do I tell what the correct path is? Whenever I do this it applies the skin to all maps until I take the file out of my wc directory.