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Attach the two feed wires from a DC source (up to 30 VDC with this unit) - I'd set up for one or two more AA's/Eneloops than your voltage goal and regulate the load back to the desired voltage - the potentiometer screw on the "blue thingy".
Then build what ever type power cable connection(s) you need to feed the "dummy battery" that goes in the Q-body. With an intermediate plug and jacks you can provide many different types of solutions. Radio Shack has all the connectors you'll need.
The units are cheap enough it's best to simply set one up and label it for each type/voltage of power source you're likely to want to use so you don't have to fiddle with voltage-out adjustments.
You want to choose an aux power source with a generous amp-hr rating for extended operating time. A large D- or C-cell battery pack for instance will last a very long time compared to the camera battery. Or, you could feed it with an AC power-brick when AC power is available and shoot 'forever'. A 12 VDC auto or garden tractor battery or 6 VDC dry cell lantern battery are a possibility too. The VR + 9VDC battery is very compact, has good amp/hr endurance and fits in a small lens case for protection and portability. The freebie flash lights given away by Harbor Freight can easily be converted to 4.5 VDC power packs with switches by tapping to LED power feed points.
Lot's of video for building these on line. Look for " DIY battery pack" etc.