The RGB Gunwale, Step and Strip lights, the Black or white wire connects to V+ (or connects to 12 volts) then the Red, Green and Blue wires go to the appropriate channels outlined in this video (Red ch.1, Green ch.2, Blue ch.3)
In some cases, the RGB strip lights will have a WHITE wire instead of BLACK.
If you are not using a controller, you can create different colors simply by connecting the black wire to 12v and then grounding the Red, Green or Blue wires. (example: Red/Blue = Purple)
Your controller may not look like this one, no big deal, they connect the same
PROFESSIONAL INSTALLATION REQUIRED!