Mods aren't installing properly?

So I've been trying to install some mods into BeamNG but I can't get them to work. I downloaded lots and put them into the BeamNG\mods folder as zips, but they do not appear in the game. I looked inside one of them and saw that it was double filletedfoldered (vehicles\car\files etc) so I extracted it then put the single folder into a zip and put that in the mods folder, still nothing. What am I doing wrong?