At least on my 2010, th Parking/Emergency Brake Cable has an automatic tensioner, there is no adjustment for the cable, it does itself. Of course it may be different on earlier models.
The Parking/Emergency Brake is just a small drum brake in the hat of the rear disc brakes. (Drum-in-Hat).
Adjusting the Parking brake is just like manually adjusting drum brakes.
Only difference, it appears the access port for the star wheel is at the rear, near the 3 and 9 O'clock position, instead of the bottom of most drum brakes.
As well, you don't adjust the Drum-in-Hat Parking Brake to leave the shoes dragging slightly like regular drum brakes, once you've adjusted the shoes so that they do drag slightly, you back them off so there is no drag what-so-ever, and then a tad more after that.
If you adjust the Drum-in-Hat so that the shoes drag, they have been know to engage unintended and lock up a rear wheels while you're driving.
It's tempting to adjust the Drum-in-Hat shoes too tight, to give that real tight parking brake handle. Don't do it, I did on another Chrysler Vehicle with the same brake setup and sure enough it did suffer the unintended lock up of a rear wheel while driving, backed off the shoes the three teeth it stated in the manual for that car and it never happened again.
The Commander manual doesn't state a number for backing off the shoes, it just says to back the shoes off until there is no drag at all.