So, it’s not the easiest thing. In fact it’s one of the first things I poked into and to do it properly it takes quite a bit of time, patience, and understanding - as everything else I suppose.
the first step is to define the route you want to go.
Basic vehicle setup - no suspensions are visible or you just don’t care about it.
Adv vehicle setup - Suspensions, steering axels, etc. all present.
second step is to learn how to do it both.
This explains everything about the advanced vehicle
This explains the same thing you could learn by just exporting the FBX and picking it apart, but it also gives you a PHAT run-down.
This explains the basics of how it works.
This guy talks a lot, but some of it is good info
This is a good supplementalhttps://youtube.com/watch?v=mPlVrq8wtSI
This explains my way for getting a steering-wheel to animate as well
IF you happen to follow any of those and you end up with a floating vehicle, the answer is that the wheel value is Radius, not Diameter - and the actually collision of it is probably hidden so just go and re-check your wheel values.