Other end same connector, onto the back of the gauge. And on teh other terminal on teh gauge you need, as BMC said, a stabilised voltage feed. Thatll be either from the fuel guage (light green) if you have the later black faced speedo, or off a stabiliser that you'll have to buy and fit.
It's a doddle really, just make sure to feed the wiring carefully to prevent chafing or rubbing - I'd be tempted to tape it up into the loom and apss it through the same grommet in the bulkhead to keep it neat and safe
