- Open the Withings App.
- Tap on Profile.
- Scroll to Family and Tap Add another user... .
- Fill in the information and tap Next.
- Fill in the information and tap Create.
https://support.withings.com/hc/ja/sections/6216033813649-Withings-App-Android
https://support.withings.com/hc/ja/sections/200501778-Tutorials