You disassemble the scuba unit in the opposite order the gear was assembled. However, a couple steps are added to the process.

1. Turn the valve knob clockwise until it's completely closed.
2. Press the 2nd stage's purge button to release all the air pressure from the hoses.
3. Remove the low-pressure hose from the power inflator.
4. Remove the 1st stage from the cylinder valve.
5. Dry the dust cap with a towel, and tighten the dust cap in the 1st stage.
6. Remove the cylinder from the BCD.