How to create an addon for UWP game for windows 10 and xbox one

i am making a game which is free however i am planning to add new maps to my game in the form of paid addons, however i do not know how to make one and implement it. the documentation is very sparce and i am wondering if anyone has pulled this off and got an addon to work. so far i have only worked out how to create a listing for it in the developer dashboard, if anyone is wondering i am using unity to make my game. again if anyone knows how to implement this then please let me know

 

https://forum.unity.com/threads/xbox-and-dlc-what-is-the-general-workflow-for-this.513888/