Apple Watch Series 3 update stuck on preparing

Hello Elijah556A,

If the Apple Watch has not progressed in some time, we would suggest restarting it. Follow the steps outlined here: Restart your Apple Watch - Apple Support

Once it restarts, try updating again. Be sure to follow these steps: Update your Apple Watch - Apple Support

Here are some tips from that page:

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.

Have a good day.