Stratus has two modes:
Master Mode
In this mode, the Multiknob is used as a master output volume control and Looper switch. When the looper is disengaged, turning the Multiknob will adjust Stratus' output volume. While looping, turning the Multiknob will adjust the volume level of your loop rather than the output volume.
Instructions for the Looper can be found here.
Live Mode - Stompbox Control
In this mode, the Multiknob is used as an "effect selector". Clicking the Multiknob will select the next effect to the right of the currently selected effect in your chain, and turning the Multiknob allows for more precise effect selection. Pressing and holding the Multiknob alternates between Stompbox Control and Preset Control.
Note that the looper and volume control functions are not available while in Live Mode.
Instructions for Live Mode can be found here.
Live Mode - Preset Control
In this mode, the Multiknob is used as a "preset pair selector". Clicking the Multiknob will select the next preset pair to the right of the currently selected preset pair, and turning the Multiknob allows for more precise preset pair selection. Pressing and holding the Multiknob alternates between Stompbox Control and Preset Control.
Note that the looper and volume control functions are not available while in Live Mode.
Instructions for Live Mode can be found here.