You already learned how to set up lights in Unity in Chapter 6, Importing to a professional game application: Unity 3D. That's the correct way of doing it for the most accuracy and realism. In order to get started more quickly though, you can set the level of ambient light. Ambient light is a term referring to the amount of light that's kind of just there. You don't see where it's coming from, so it casts no shadows; it's pretty boring, but it does the trick. Why not use it now to get up and running, and add more realistic lighting when you get the time?