After detaching the ring from the volume knob's circuit board, you can screw the ring component to the volume knob casing for easier re-assembly.

Align the screw holes between the two components. Using the 2 (3mm) screws from step 10, screw them together, as shown in the 2nd picture.

Simply align the snap-fit joints back together to reassemble the main volume knob component.

The snap-fit joints are highlighted in the 3rd picture.