A few weeks ago, I bought the Samsung Gear Fit 2, and because I'm a hobby programmer, I tried to make an app for it, and the making of an web-based app in Tizen Studio worked very well.
EDIT: I solved the problem. I had to create a Samsung certificate. The second problem was that I had to set the minimum Tizen version to 2.3.1 because the Gear Fit 2 does not support higher versions. And finally I was able to install the app on my Gear Fit 2.
The app is called "Calculator". When I try to install the app on my Watch, a Error shows:
Launching Calculator has encountered a problem.
Installing the package... > FailDetails:
Installing the package... > Fail
Unexpected error occurred at the below step.
'Installing the package...'
Please try again later.
Welcome to Tizen! :) Tizen Web App is very easy and fun.
If you want to install your app on your watch (Samsung Commercial Device), you have to use Samsung distributor certificate. Because it is Samsung Gear security policy.
You can see how to generate Samsung certificate and install on device at below material.
See "1_tizen_studio_windows.pdf" -> "Running Applications on a Target Device" 48 page.
https://developer.tizen.org/community/tip-tech/developing-tizen-apps-tizen-studio
Good luck!