Hey guys, I've learned that you can add information on a car mod to the car in the JSON file, but how do you go about doing that? And, also, what else can you do with the JSONS?
Take a look at the files included with the game. They already contain examples of most available functionality. The vehicles are all located in BeamNG.drive\content\vehicles, so for example that might be here or a similar place: C:\Program Files (x86)\Steam\SteamApps\common\BeamNG.drive\content\vehicles You'll want to unzip one of the vehicles somewhere else (make a folder in your Documents or on your Desktop) and then take a look at what's in there.
+1 on previous, take a look at the game's files. They have a lot of functionality. For example, an engine.json directly controls a vehicle's engine and transmission.
That's not really accurate. You are thinking of jbeam files, not json files. The game generally uses json files for descriptive information. This is as opposed to the jbeam files it uses for functional information (data).