Turn on the power switch and select the corresponding gear according to the road conditions. According to Xiaomi official website's query, S2 power-assisted mode has three gears, 1 gear provides 25% power output, gear 2 provides 50% power output, and gear 3 provides 75% power output. When riding on some uphill roads or against the wind, it will provide power through the rear wheel motor to reduce the physical consumption of riders.