The recommended and usual method is to wire additional spotlights (driving lights) through the appropriate fuses and a relay triggered by the main beam headlight wiring. There are some postings on the forum about exactly how to do it.
Some users have also wired in a switch to provide more control over the lights, such as being able to turn them off completely or turn them on all the time, as well as having them switch with the headlights.
The two wires you have coming out of each new light fitting are the ground and the switched feed wires, black is usually the ground wire but you might have to open the light unit to check which is which.