In YUDU Publisher, it is possible to organize your content in the following structure:

Folders are NOT compulsory, and are largely a further method of organizing your content.
Publications Groups are compulsory and it is within these that you create your digital publications (termed editions on the system).
If you have a custom-branded iOS, Android and/or Windows application, then your app will point at the publication Group containing your digital publications.
A single YUDU Publisher account can contain one or more publication groups, either to accommodate multiple magazine titles, catalogue brands, or document types, for instance.
Admin users can be created at any of these levels within Publisher (main client node, folder, publication group or an individual edition), each with their own unique set of permissions.
You may have clients of your own that login directly to a specific folder or publication group in order to manage their own titles, for example. Those admins would not have access to anything outside that folder or group, and you can specific the extent of their access, e.g. reports only, reports and publishing, subscription management, etc.
Within your applications, you can also set up custom categories, and these can also be used to filter publications within a group folder on YUDU Publisher.