Help needed with 106

It is underneath, though you may have to remove the heatshield if there is one fitted. Look for where the handbrake rod comes through the floor, and where the cables are fitted to the rod there is a 13mm adjusting nut. But be aware that the rear shoes should be adjusted first. If the self adjusters would ever work properly on rear brakes, then the handbrake would seldom need asjusting! So the correct procedure is to de-adjust the cable first, then adjust the shoes, then adjust the cable to 4 notches.

If its anything like the 205 system 4 notches is lethal. When the MOT guy adjusted mine to lock at 7 notches hitting a large bump in the road (big bouncey one, not a short stuttery bump) would lock the back wheels with a screech. After that he advised me to always adjust it before and undo it afterwards. J