Basic Electronics Help Needed !!

[Ferret_san]

Hi Guys. Hoping someone here with some basic electronics knowledge can
help me out. My nephew is doing a class project and wants to make a simple
working traffic light.

Because I have a very limited understanding of electronics <cough> none
<cough> I'm hoping someone can show me the wiring diagram that I'd need
to put together.

Basic plan is to use 3 flash light bulbs and hook them up to a simple 3
way slide switch and battery pack (2 AA batteries or 9 volt ?),so the left
position illuminates the red light, the middle illuminates yellow, and the
right position illuminates the green.

A further on/off switch will also be included for the power.

Anybody feeling generous that can help me out with the wiring ?

Nothing fancy, just something simple enough for him to explain how it works,
and how it was wired.