Try the forum for Adobe Digital Editions.
Install the Bluefire app to read DRM ebooks. Register it with the same AdobeID as on any PC/Mac.
You can transfer books from PC using Dropbox, iTunes or email yourself.
Then open with Bluefire.
(Apple like to make life hard for iPad users, so don't allow simple file copy like Android does).
Install the Overdrive app to borrow, download and read DRM library books.