For starters you will want to run the same amount of wiring that is used on the right landing light for the additional left landing light.
In addition to that, you will need to run one additional wire to sync the wig-wag. The additional wire will run from master out to slave in on the lights. Since the right landing light is the "standard" light, I ran the sync wire from the right landing light's master out to the left landing light's slave in. The additional wire converts the pulse mode to a wig-wag mode when the panel switch is rocked to pulse.
Oh, additionally the pulse power wire will need to be tapped (Y) in the fuselage so pulse power that normally goes to the right landing light is also applied to the left landing light. The same goes for the landing light steady on power wire as well.
Below are links showing the wiring at the lights and the blue amp wing connector. At the blue amp connectors I used the vacant pin 3 for the wig-wag sync wire.
If you have any additional questions, PM me with your phone number and we can discuss what is needed in more detail.