help with TR7 unit for alpine

i just bought the TR7 box for the alpine tv and it says to wire the black to ground, red to 12v (assuming i can splice into red harness cable wire), green wire to alpines WHITE/ blue wire. i understand all that. it says the blue wire goes to alpine footbrake input and green wire to alpines hand brake input. what are the inputs, what does that mean.

i believe they mean by blue wire to footbrake as the brake swtich wire (will read 12v when you step on the brake) and the green handbrake is the wire that attaches to the parking brake (should only be 1 wire, it sends signal to illuminate the dummy light on the dash)