When you click to download an ebrary record, a dialog box opens containing a link to Adobe Digital Editions:
Click on the Adobe Digital Editions link.
Follow the prompts to download and install Adobe Digital Editions on your PC.
Make a note of the username and password you used to created your Adobe account. You'll need them later when you authorize your Nook. [You only need to do this step once.]
Then, Choose the download option "Download the entire document for 14 days in Adobe Digital Editions format" and click OK.
Click the "Save File" button, then click OK.