Calibrating the Automatic N380 Shifting System:
1. Turn system power on
2. Pedal the bicycle lightly through the entire calibration procedure (while riding, or in a repair stand)
3. Press and hold the "mode" button (the silver/chrome button on the shifter) until the rear hub begins shifting (5-7 seconds typically), then release the button.
4. Continue pedaling lightly while the system shifts from "low" to "high" ratio multiple times and completes the calibration.
You should hear the hub interface (black part by the wheel) make some noise during this process. Once complete, the shifter will stop flashing. If unsuccessful, unplug the interface down by the wheel, and reconnect - then repeat the procedure.
Here is a link to download the complete manual for your reference:
Here's a video on the procedure as well!