If it's for windows then you are better with with stand-alone ereader installed with Calibre.
Ominously the specs have no mention of formats supported and it does mention using it to buy books from them and read your own DRM free books.
If you've installed and it won't display an epub OR mobi/kindle from
www.gutenberg.org (download both) see does it open PDFs. Maybe it's just junk, or not an eBook reader at all but just for PDFs.