What Gruftlord said. Basically the manual (7zip) version is made in a way that you need to copy the content into NWN directory. Or copy the archive there and extract as is (not into new folder). Allow overwrite everything.
I recommend to get installer version though - that one keeps eye on your version and will inform you if you try to install it on wrong one. The only supported version is english 1.69 properly patched (if you have GOG you need to first repatch)