It’s a pretty simple process to add ebooks to your ereader. The file extension for an iPad and a Nook is .epub. The file extension for a Kindle is .mobi, although it is possible for a Kindle to convert an .epub file to a .mobi. Mostly it’s a drag and drop process. I’ve put links here for you that illustrate the process.
Instructions for iPad and iPhone:
http://www.codenamedesign.com/blog/how-to-add-an-epub-file-to-an-iphone-or-ipad
Instructions for Kindle:
http://www.amazon.com/gp/help/customer/display.html?nodeId=201243040
Instructions for Nook:
http://www.youtube.com/watch?v=O5XFRnutIfI
With computers, there’s generally more than one way to accomplish a task. I’ve found these to be efficient.