How do I add skins to maps?

I read the tuts on adding models and icons, I understand them fine, but now I must ask anyone who knows, how do you add skins to maps?

you add a skin to a map by first converting it to a .blp, then you import it into war3editor in the import manager and use a custom path and set it to the unit you want it on. If you have any other questions or want more details just ask

ok, its a blp, but the question is what directory would I place it in and what would I name it exactly to replace a hydralisk skin?

would it be Units\Critters\Hydralisk\Hlisk.blp ?