Once the proper configuration profile has been installed from the Apple Developer Center, the new watchOS beta can be downloaded through the dedicated Apple Watch app on the iPhone by going to General --> Software update.
To install the update, the Apple Watch needs to have at least 50 percent battery, it must be placed on the charger, and it has to be in range of the iPhone.
There were no new features discovered in the watchOS 5.3 update, suggesting that it focuses on bug fixes and under-the-hood performance improvements.
There could also be hidden changes that will be available after the update is released, such as support for the upcoming Apple Card, set to debut this summer. If new features are discovered in the second watchOS 5.3 beta, we'll update this post with details.