The cog adjuster takes up the play between the shoe and the drum (inside of rotor hat). The cable adjuster takes up the cable slack. Both are adjusted as a system.Yeah, but OP is asking WHY to do it this way instead of at the handle. I have always wanted to know as well. I don't see why it matters which end of a cable gets tightened, but if there is a real reason out there I'd like to hear it too.
Loosen cable, adjust cog, tighten cable. Per TIS, parking brake must hold the car in 4-7 clicks. I always adjust mine to 4 so it lasts a while.