Remove rear wheels,
release handbrake,
turn hub/disc until the hole lines up with adjuster (inside drum,star shape thingy)
Lever/turn adjuster clockwise with mid sized flat screwdriver through the hole, until the disc becomes hard to turn,
then back it of one click,so disc turns freely(or until you can feel/hear the shoes slightly grazing the drum).
Job done.
Note,sometimes when you have tightened them so that you can hardly move the disc and you give the hub face a tap with a hammer,this centalizes the shoes and releases the disc,so that you can get a ultra fine adjustment and even less movement at the handbrake lever.
It really is a very easy job,that makes all the difference to the handbrake performance.
Dan