- If you're weighing a baby, make sure you install and lock the baby cradle.
- Turn the scale on by touching the main button.
- If you put a blanket on the cradle, touch the button again to tare the scale.
- Place your baby on the cradle or let your child stand on the scale, facing the screen.
https://support.withings.com/hc/zh-cn/sections/6216371591569-Smart-Kid-Scale
https://support.withings.com/hc/zh-cn/sections/200508097-Tutorials