P-hotkey: "Patrols between two or more spots. Attacks and follows incoming units "
"A combination of waypoints (Shift) and the patrol command enables a unit to patrol up to ten different spots on the map"
If you do a shift-patrol command with a unit it will start a line-patrol (point to point) and re-doing this command will just reset patrol from your current unit location.
Whats needed is a primer 'Move' command by using rightclick on a location far enough for you to finish the patrol route you want, up to 8 Patrol locations.
Patrol can also be used on workers by adding an additional unit to the selection that has the Patrol ability, once you are done with patrol route you can reuse that unit and let the worker patrol by itself.
Example:
Replay: https://ufile.io/g8xbfz8h
Real game: