I've wondered the same thing and did not find clear instructions about how to use the
Nautilus controls.
See this post for all the details. Regarding just winterizing, here is item #6 from that post:
6.
Winterize your plumbing lines and fixtures
Handles position "Tank Fill"
Open low point drains, all faucets, remove hot water tank anode, remove refrigerator water filter
Turn handles to 45 degree angles
Air Pressure Hose to Right Inlet (40 PSI max) for a few minutes
Close low point drains, faucets, return hot water tank anode
Handles position to "Winterize" - Set water heater to BYPASS
Hose from Antifreeze into Left Inlet - Turn on Water Pump
Open each plumbing fixture until solution appears then close
Turn off main water pump
Switch small fresh water hose from 5 gallon fresh bottle to Antifreeze
Turn on kitchen water pump
Run drinking water on refrigerator and sink drinking spout until solution appears
Wait one day and confirm ice maker contains solution
Turn off kitchen water pump and remove fresh water hose from Antifreeze