I am having a very hard time installing levels! I have gone into my steamapps, common, beamng, content, levels and I have dropped my zipped folders into there but when I try to start the game there are no extra maps. Do I have to press something in game or am I just doing this completely wrong. Any help would be greatly appreciated! - Mike
You have to: 1. NEVER place zipped files unextracted. 2. ALWAYS put mods in documents/beamng/mods/ Under the mods folder, create two folders named "vehicles" and "levels". When you open the zip file containing your mod, you'll notice it the first folder is "vehicles" or "levels" depending on what it is. On your windows explorer, make sure you have the "mods" folder opened, showing vehicles and levels folders. In the zip containing your mod, make sure it says vehicles or mods, not what's inside the folder. DON'T double click this folder. Instead, drag it over into explorer, into a blank space, NOT over one of the folders. This ensures you put the contents of your mod correctly into the folder, instead of messing it up and doubling it (mods/vehicles/bmwm30 instead of mods/vehicles/vehicles/bmwm30, which is wrong)
That's the way it used to be. You would assume it still works as that's how the default ingame vehicles work, but apparently that's not the case. Since the game went onto Steam, the new way to install mods is to drop the zipped file into the mods folder in Documents\BeamNG.drive. Although for older mods I believe you still have to do it the way you tried, assuming the mod is even still supported.
Just check this handy guide that explains mod installation in details: http://www.beamng.com/threads/12872-Guide-to-mod-installation-for-0-4-0-0-and-up