To remove the power supply unit, unlatch and remove the base cover. Unlatch and remove the front bezel. Then flip the front panel over to access the inside of the system. Identify the power supply unit and disconnect the cables. Remove the 3 screws. Unlatch and lift the unit out of the system.
To reinstall the power supply unit, place it back in the system and latch it into place. Reinstall the 3 screws and reconnect the cables. Flip the front panel over to cover the system, secure the front bezel and base cover on the system.