To restart an Apple Watch, follow these steps:

• Normal Restart:
  1. Hold down the side button until the power menu appears.
  2. Tap the "Power Off" slider and slide it to turn off the watch.
  3. After it shuts down, press and hold the side button again until the Apple logo appears to turn it back on.
     Note: You cannot restart the watch while it is charging

• Force Restart (if the watch is unresponsive):
  1. Press and hold both the side button and the Digital Crown simultaneously.
  2. Keep holding both buttons for at least 10 seconds until the Apple logo appears.
  3. Release the buttons and wait for the watch to reboot.
     This method forces the watch to shut down and reload without deleting any data

This force restart is useful if the watch is frozen or not responding properly. It does not erase any content or settings. For a full reset that erases all data, other steps are required