**See this topic f**or information on how to get the Author and Distributor Certificates and install a watch face on a Tizen Watch. Especially the 39th more so the 81st thread where it has a better details of the process.
Are you sure you want to design for Tizen based watches. They are very old and not supported. Galaxy Watch4, 5 and 6 run on Wear OS and use Watch Face Studio for designing those watch faces.
Ron
Samsung Developer Relations