Here are three videos displaying my introductory assignments with the Arduino microprocessor.  First, I merely tested to make sure I could write a simple script to turn an LED on and OFF.

Next I set up my breadboard accordingly and created a simple switch by breaking the current between the LED and the board.

Using an input on the arduino, I was able to detect if the switch was open or closed.  By adding some bolean logic (true or false) to the code I could then alternate LEDs by the switch being opened or closed.