Cannot get pin-joint-type arm segments (like a cardboard puppet) to work.

Oh my! I've been at this for days now. My puppet arms are made of individual segments and I would like to use draggable handles to adjust the position for pose-to-pose recordings. The closest I've gotten was by trying a method suggested by @alank99101739 (https://community.adobe.com/t5/character-animator-discussions/segmented-arms-that-work-like-an-actual-puppet-w-examples/m-p/11251336) but maybe my puppet hierarchy or my behaviors are messed up, because I can't get it to work. The idea is to nest the independent arm segments so the Lower Arm is inside the Upper Arm layer, and the Hand is inside of the Lower Arm layer. Then we connect ("Attach to") the Upper Arm to the Body, the Lower Arm to the Upper Arm and the Hand to the Lower Arm. Finally we add draggable handles to each segment at the end opposite to its origin/attachment point. If we do that I it should behave like a real cardboard puppet with pin joints. Well, the arm segments in my puppet pivot at their origins but the origins are not following their parent movements. WHAT AM I MISSING!! I'll appreciate any info you could share one this.