I have downloaded the sony reader application on Nexus 7 2012 16Gb and then transferred three epub files to the memory of N7. Initially I had put these eBooks in N7 memory and not in a specific folder as there was no folder called books or ebooks. When I was not able to see those epubs on N7, I transfered to the "download" folder but sony reader is unable to locate those files. How do I get my sony reader to access those ebooks?