The wiring goes ... hub ->headlight->taillight, the taillight is hooked up to the headlight
headlight is wired to the plugs into the hub-dynamo.

heat shrink tubing can be slipped over the wires and , with heat , the tubing shrinks
to cover connections and potential abrasion points ..

as previously discussed this one adds a USB power plug to charge your I widgets as you ride.

https://www.bike24.net/1.php?product...gc=0;orderby=2