After Do Not Disturb mode is enabled, the watch does not vibrate to remind you when it receives incoming calls, text messages, and other alerts.
Slide down on the watch face and tap the Do Not Disturb icon to select Do Not Disturb mode.
Enable Do Not Disturb: The watch immediately enters Do Not Disturb mode.
Scheduled DND: You can set the start time and end time of DND mode.
Auto Enable: After you fall asleep wearing the watch, the watch automatically enters and exits DND mode.
Set method: Watch settings>Preferences>Do Not Disturb>Auto Enable