For Tracks dont delete them and hide the Hull, so that there only Wheels and Track. Then select them like the hull in the Video and klick on a ball you want and do the same like in the Tutorial. The Material go only at the Meshes who are select.
That should be the light Settings. I will look what you can do against this^^
€dit: Don´t forget, this is an Imported Object, so the Track will look very crazy^^