If you're having trouble installing an Apple Watch update, it's likely because your iPhone isn't running the latest version of iOS, or because there's not enough space on your Apple Watch. Here are a few things you can try:
-Update your iPhone to the latest version of iOS.
-Connect your iPhone to iTunes and update your Apple Watch through there.
-Delete some apps or files from your Apple Watch to free up space.
If none of those work, reach out to Apple Support for more help.