In the Sugarmate app
Go through the Apple Watch setup process for User #1
Tap Advanced Options on the Apple Watch page
Turn on Multi-user Support
Tap the ☰ in the top left
Tap “signed in: [name]” at the bottom
Tap the ✎ in the top right and update User #1’s nickname
Tap Add Another User
Sign in as User #2
Repeat steps 1-6 for User #2
User the Siri watch face to see both users’ readings simultaneously