Install Tessie for Apple Watch
On your iPhone, open the Watch app.
Scroll down to Installed on Apple Watch. If Tessie is listed here, the app is already installed and you can to open it from your Apple Watch app screen.
If Tessie isn't listed above, scroll down to Available Apps. Tap Install to install it on your Apple Watch.
If you're not being signed in automatically
First, restart both devices and then open Tessie on your iPhone.
If you're still not signed in on your Apple Watch, pending software updates might be preventing syncing between your devices. Apply any pending updates on both devices and then open Tessie on your iPhone.
If the app isn't listed under available or installed apps
Your Apple Watch might not be supported. Tessie requires functionality introduced by Apple in WatchOS 7.0. WatchOS 7.0+ is supported on Apple Watch Series 3 and up.
You can verify your WatchOS version in the Watch app by going to General > About > Version.