Open the Settings app on your Apple Watch
Tap General
Scroll down and tap Reset
Tap Erase All Content and Settings
Enter your passcode if prompted
Confirm by tapping...
Open the Settings app on your Apple Watch
Tap General
Scroll down and tap Reset
Choose one option:
Reset All Settings
Erase All Content and Settings
If prompted, enter your...
Open the Health app on your iPhone
Tap Browse
Tap Sleep
Follow the on-screen setup steps to enable Sleep tracking
Set your Sleep Schedule
Set your Wind Down and...