Once installed I simply opened the ePUB files that I checked out & downloaded with Adobe Digital Edition, and then converted them from within Calibre (right click on any book and select "Convert Books -> Convert Individually" and select MOBI as the output format. A “Success” dialog will appear, saying that the plug-in has been installed. Click on the “Yes” button in the “Are you sure?” warning dialog that appears.
Click on the “Add” (sometimes “Open”) button. Please note: to open this eBook you need Adobe Digital Editions.Select the DeDRM_plugin.zip file in that folder.Click on the large “Load plugin from file” button.Click on Plugins (under “Advanced”) - it looks like a jigsaw puzzle piece.However for the ePUB formatted books I had to download Adobe Digital Edition to download the books. For the Kindle I was able to transfer them without much effort to my Paperwhite. My local library provides books in a variety of formats, ePUB and Kindle being 2 of them. From the Preferences menu select “Change calibre behavior”. I recently purchased a Kindle Paperwhite. Download the latest tools package, and unzip it.
General steps to install the DeDRM plugin I don't like that I have to do this just to gain access to public library books on my Kindle but saw no other way to accomplish this. Cambridge Library Collection gives todays readers access to. The simplest method I found was to install Calibre along with the DeDRM plugin. An electronic version of this title is available for institutional purchase via Cambridge Core.