An e-book or digital book is simply an electronic version of a book that you download and save to your computer. Instead of going to the bookstore or waiting for the mail to deliver a hard copy book, you get instant access to your product through the magic of the internet. Once you place your order, you'll be taken to a page with instructions on how to download your purchase right away.
You'll also receive and email with the download links as a backup. Once you download the materials to your computer (which only takes a few minutes), you'll save them as a PDF file. A PDF file is a readable document file that you can also print out if you desire a hard copy version of any portion of the your purchase. You'll need the Adobe PDF reader to view these downloads, which is installed on most newer computers.
If you do not have Adobe PDF reader, you can download it for free here: http://get.adobe.com/reader/?promoid=JZEFU.