Kerby,
Any on/off switch will have two wires. One of the wires (red) needs to connect to accessory power supply. Connect red to a wire that gets power when you turn your key on.
The other switch wire (brown) provides power to the lights, connect brown to the two blue/white wires.
As you stated the black wires are ground. Connect to any existing ground wire, or find a good ground point on the bike.
Test this before soldering or crimping connectors. I recommend soldering.
If I had a wiring diagram for the light bar I would send you a copy.
I hope this helps. Let me know, Mark (caseml)
