Yhe apple watch don’t want to do the software update

Try these steps:

1. Make sure that your Apple Watch connects to its charger. 
2. Restart your Apple Watch. Press and hold the side button until you see Power Off, then drag the slider. To turn your watch on again, press and hold the side button.
3. Restart your paired iPhone.
4. Try to start the update again. 

If the update won't start, open the Watch app on your iPhone, tap General > Usage > Software Update, then delete the update file. After you delete the file, try to download and install watchOS again.

Learn what to do if you see 'Cannot Install Update' when updating Apple Watch.

Update directly on your Apple Watch

1. Make sure that your watch is connected to Wi-Fi.
2. On your watch, open the Settings app.
3. Tap General > Software Update.
4. Tap Install if a software update is available, then follow the onscreen instructions.

Update your Apple Watch - Apple Support (IN)