I have created a couple different custom apps to try to proof social sharing and I have created a folio with metered and free articles and published it private and free, and I have read everything (I think). I cannot get the navigation bar to show the "heads up display" for social sharing. Why?
Folios published as private won't appear in your custom viewer app. You need to publish the folios as public, and you need to enable social sharing in both DPS App Builder and in the application account (using the Account Admin tool).