how to implement app settings

Please help me to instruct how to implement settings for watch face.

I found an article below but I have no idea where to write tags for <properties> and <settings>  in this page.

https://developer.garmin.com/connect-iq/core-topics/properties-and-app-settings/

Should I create a new file for it ?

If I can learn it by reviewing sample projects that enable settings in SDK, it will be appreciated.