Creating a New Track

In Unity:

1. File -> New Scene
2. Delete the "Main Camera"
3. Open the Projects tab in the bottom, and drag the Car, GameManager and UI (make sure you drag the blue cubes, not the scripts!) to your scene.
4. Click on the car, and under "Custom Car Control" click on the target symbol next to "Speed Text". Select "Speed".
5. You should be done! Check the console for warnings, and then work on your terrain!

Notes

The Car, GameManager and UI are stored as prefabs. Learn more at https://docs.unity3d.com/Manual/Prefabs.html