The other 3 channels are on the left hand side, the other blue screw connector.
So you could connect the RGB channels of the LEDs to 49, 50, 51 and common anode to 12V. The negative side of the 12V supply to the GND screw terminal.
One other step is to run WinIPAC and check the "enable high current outputs" box.
Note that if you are referring to addressable LED strings, that would be different, we have a different controller for those, the NanoLED.