Hello, the docs you linked are to list all the folders. It sounds like you want listFiles which returns the url of the file within the object. If you have tried this and it is not working, i would reccomend adding the code snippet you tried, what is returning, and how it is different from what you expect so that folks in the community will be able to help
https://www.wix.com/velo/reference/wix-media-backend/mediamanager-obj/listfiles