Step 3: Determine what the wires do.
The two white wires should be the pair that closes the switch that lets you know when the dial is turned. The blue and green wire should be the pair that lets you know what number was dialed.
As such, when you turn the dial, the LED connected to the white wires should turn on, and when you let go of the dial, the LED connected to the blue and green wires should blink on and off as many times as the number you dialed (see video).
For instance, if you dial 8, the LED connected to the green and blue wire will turn off and on 8 times. This happens because one way to dial a phone number is to rapidly break the connection the number of times for the digit you are trying to dial. So, again, to dial an 8 you would have to rapidly break the connection 8 times.