YUDU Publisher has an operating system like structure in the sense that there are main folders, by which you can have sub folders, and within those you would have files.
In Publisher, one can organise their content in the following structure:
An real world example of this structure could be that a publisher owns a magazine and leaflet, each of which are regional. The Folder could be the region, the Group would be the name of the leaflet and magazine, and within those would reside the individual Publications:
Folders are NOT compulsory, they are simply a further method of organisation. Should you wish, one can create a Group node and then populate this with Publications.