You can load books via calibre. Open Calibre, plug in the reader, turn on USB storage using the reader's android screen. Calibre will detect the reader as noted by the icon on the top bar in Calibre. Click on any epub book in your library and hit the send to device button. You can DL books from anywhere and add them to your Calibre library.

I think you can even send books as attachments to email (I haven't tried yet).