As explained there, ZotFile can help sync the files with a cloud storage service such as Dropbox so that you can annotate on your iPad, and then it can extract annotations from the files into Zotero notes back on your desktop.
Thanks adamsmith. So then, is Zotero storage irrelevant if I use ZotFile for this purpose? Must I use Dropbox or similar service for my storage in total?
@hmclemore: It depends what exactly you're trying to do. The function being discussed here copies specific files from your Zotero library back and forth to a given cloud storage location on your computer so that you can access them from a tablet. Those files could still be stored files in Zotero that are synced via Zotero Storage to your other computers and zotero.org.
I'm using Zotero Storage; must I still use a different storage service such as Dropbox for this function?