Apple Seeds First Beta of watchOS 8 to Developers
To install watchOS 8, developers will need to download the configuration profile from the Apple Developer Center. Once installed, watchOS 8 can be downloaded through the dedicated Apple Watch app on the iPhone by going to General > Software update.
To update to new software, an Apple Watch needs to have 50 percent battery life, it must be placed on the charger, and it needs to be in range of the iPhone. It's not recommended to install watchOS 8 on a main Apple Watch as the software may be unstable at this early date.
watchOS 8 is limited to developers at the current time, but Apple plans to provide a public beta later this year ahead of the software's fall launch.