[isaacdl]

Blue and brown should be wired to the power distribution board, on a 20 amp circuit. I believe blue is positive and brown is negative, but double check that on the back of the sensor.
Pick white or black. It doesn't matter, as long as you use the same one for all three sensors. Wire that color to the "Sig" pin on one of the digital inputs on the digital sidecar. (You'll probably want to use PWM cables, just cut off the male end and cut/tape off the other two leads.)

Edit: You don't need the other color (white or black). Just tape it off. The reason there's two is that you can choose whether the sensor will send a "1" (high value) when it senses dark or whether it'll send the "1" when it senses a light color. It does make a slight difference in programming, but it's not terribly difficult.

2nd Edit: I believe that DO refers to "Dark out" and LO...well, you can guess.