I'd like to make a vehicle, but I currently do not know how to create nor program a vehicle to add in-game. How do I do this?
Making vehicles for BeamNG is particularly hard. A lot of people use Blender for modelling, but understanding Blender is a very difficult task. Sketchup is easier to understand, but cannot do crucial things like UV mapping. For programs, you'd simply need Notepad, Notepad ++, and any preferred graphics program, like MS Paint, Photoshop, Gimp, and Paint.net. That of course is just scraping the top of the iceberg. There's more to it than that, like jbeams for example, which is what makes the deformations possible.
Agreed... it is a rather long winded process that, while not inherently challenging to do as a whole, does take a lot of built up knowledge to understand and do it properly. My suggestion, start with modeling the car you want to model. Once you do that, you then have a very good basis on which to form the JBeam around. Then, bring both into the game one piece at a time. If you JBeam your vehicle first and then try to model it, you will just make a mess for yourself down the road, so this is the definit recommended strategy.