Normally there should be two dangling wires, one short with connectors for the rear light (these ones are visible on your light) and a longer one that you connect to the dyno (and trim if necessary) using eg this if you have an SP hub . This last one doesn't appear to be visible on your photo so you may need to open up the light and do some soldering?
Normally there should be two dangling wires, one short with connectors for the rear light (these ones are visible on your light) and a longer one that you connect to the dyno (and trim if necessary) using eg this if you have an SP hub . This last one doesn't appear to be visible on your photo so you may need to open up the light and do some soldering?
user instructions for more info