The heart of this hub is the sequencer which allows selection between high and low gear.
For all 4 videos on the 2-speed red band hub: https://www.youtube.com/playlist?list=PL3n0ffUd1sKOxrUMZB2vA6na1EZS3lnuE
For more information on the red band 2-speeds and later yellow and blue band 2-speeds,
visit https://www.sheldonbrown.com/sutherland/CB-IGH-3-bendix.pdf and download this pdf for ready reference.