Unfortunately, time is a limited resource and we don't write as much documentation as needed.
Concerning the TaPD plugin, the user manual is fairly complete but covers only v0.1. It is also available as an archive file. A tentative for a new user guide is available, both online or as a PDF file. Only the Introduction is available (with new screenshots).
Ultimately, all documentation will be delivered through the Help Plugin, which is of great assistance since it allows browsing of manuals within AoI.