^^^^12-2 Would have Black, White, and a ground. 12-3 Would have black red and white plus a ground. Unless you have some funky wire, eh? Did you pick it up in canada? haha
The 12-2 will be fine, the requirement for this circuit is probably only 14-2 if it is a 15Amp circuit. As for wiring the ground, there should be 3 wires, an unsheathed copper wire, and 2 sheathed copper wires AKA 2 conductors. One conductor is White, and one is Black. The black is the ungrounded conductor, the white is the grounded conductor. Install 5 boxes, one above each light and a switch and run wire between all 5 boxes. So from box one, run wire into box 2 and the switch box, from box 2 run into box 3, from box 3 into 4. The switch box to the circuit breaker will be called the home run.
Now leave 4-6 extra inches of wire to work with in each box, just makes the job a little easier. Cut the outer sheathing, I am assuming yellow in color, and leave only 1/4" to 1/2" in each box.
In box one, you will have the power coming in from the switch box, lets call this the first set, so Black1, White1, and Ground1. Then the Light will have Black2, White2, Ground2. Then the wire going to box 2 will have Black3, White3, Ground3. Take a red or yellow wire nut, which ever fits better, and attach Ground1,Ground2,Ground3. Do the same with Black1,Black2,Black3 and White1,White2,White3. The blacks and whites will use separate wire nuts.
Now in all the rest of the boxes do the same thing, attach all the black together, all the whites together, and all the grounds together. If you are working with EMT, you can also just attach the grounds to the box.
In the box with the switch, simply hook up the switch, 1 black wire on 1 screw and the other black wire on the other screw. Hook the white wires to each other with a wire nut, and same with the grounds.
Did I miss anything?
go figure
for the inspector, there is no way to properly wire a home.