It all depends on how far you want to go.
This tutorial will guide you through building a car using vehiclebody, explains about it's parameters:
Youtube video
But, apart from that, I can tell from my personal experience that there's still work to do, as I understand, physics of VehicleBody is still bound to the original Godot Physics engine and not the new bullet physics integration.
I am struggling too in this.
And googling a little more I found this repo with a demo, it was for the Alpha version of 3.0:
Free roam roguelike demo by Zireael (cool gotta try it)