This is the best explanation of DCCD because it uses situational examples of each setting. You don't need to understand Japanese to understand what's going on here. I happen to understand Japanese, but even with just the video portion, I could understand.

Subaru Impreza STI JDM and DCCD use - YouTube

EDIT - I'm working on a translation for you guys.

EDIT 2 - here's my rough translation of what the dude is saying in each run. I'm missing a few tidbits here and there, but here's the gist of it. Also note that in each run, VCD is OFF.

1st run – Auto Mode – If you press the brakes hard and load the front end, the car will typically spin in this fashion. It won’t spin like this if VCD is on. Point: get use to the feeling of the rear end coming out.

2nd run – Auto Mode – it will spin in this fashion. The rear spins out easily. Even when you apply the gas, the front wheel engagement lags a bit and this is what happens. Next, we will see what happens when we react to the moment the car begins to spin easily.

3rd run – Auto Mode – in this training, we will apply the gas in order to control the car through the turn. Even if you’re scared, press the gas. As long as you’re on the gas the car won’t spin out.

4rd run – Auto Mode – in this run, the rear drifts out, at that moment, counter steer and lightly apply gas at the same time and you can generally take a good line through the turn. Point: don’t go full throttle.

5th run – Auto Mode – this is the pace you want to go through a turn, I’m really applying the gas here and going out of course a little, which I discourage, but the point is to load the front good and then counter steer/apply gas and the car will pull through via the front wheel bias.

6th run – Manual Lock – in this mode the rear does not want to drift out very much. Point: the stability of the car increases. Next run I will go faster.

7th run – Manual Lock – there is a little more understeer than Auto mode and is more stable. There isn’t big movement in the car’s core. Point: in slippery or wet conditions, it is more stable (than Auto Mode).

8th run – Manual Lock – in this mode, it is more stable but there’s too much traction on dry road. Again, it’s better when the road is slippery for this mode.

9th run – Free Mode – it moves like it’s a RWD car. Most of the power is towards the rear and the car will move in this manner.

10th run – Auto Plus Mode – this mode is similar to Manual Lock. But more than Lock Mode, the direct-feeling is less and for slippery/wet roads, Lock Mode may be better.

11th run – Auto Minus Mode – the rear drifts pretty easily. The turn-in is easier and the steering input is good.