Race game tutorial brake lights help

So about 6 months ago, I downloaded the Race Game Tutorial Package from Unity. I setted up the whole car like the tutorial "said" to. But I realized the wheels didn't turn. Now I know that I need to set up the brakes lights to make the wheels turn. But everytime I put in a material/texture in the brake lights slot, when I press play, the wheels just "glitch" out of the car. But that only happens for the rear wheels. When the car isn't touching the ground, the wheels are back on the car. When I roll at a certain speed, while turning, the wheels go back where they should be, but since I'm touching the ground, they "glitch" again. That makes the car glitch as well.

I really need anyone's help. I don't know a lot of programming or coding, just the simplest basics of Javascript and C++, and advanced HTML. Maybe I'm putting in the wrong variable or it's something else.

If anyone's had this problem before and found a solution, it would GREATLY be appreciated.

Thanks anyway for reading this.