First - try your shifter in the ORANGE mode on the handlebar. You can switch between BLUE and ORANGE using the silver button. When you’re in ORANGE, rotate the shifter away from you, which should make it easier to pedal, then towards you will make it harder to pedal. If this does not work - please follow the steps outlined below.
1. Turn system power on
2. Pedal the bicycle lightly through the entire calibration procedure:
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.
Here is a link to download the complete manual for your reference:
Also, here is a video on the procedure: https://support.enviolo.com/hc/en-us/articles/360028585211-Automatic-gripshift-H8-controller-calibration