Purchase an ebook reader. There are many types on the market, from the Amazon-based Kindle to Sony to lesser known brands. Investigate each reader to find the one that will fit your needs.
Find out if the book reader that you have is dedicated to one book site or if you can download books from multiple sites. The Kindle, for example, can only download information from Amazon, the Cool-er ebook reader can only use the Coolerebooks site. Other ebook readers, like the Sony ebook, can use many sites online.
Find the site online that you wish to use in downloading books. Each site has a procedure for signing up and setting up accounts, such as picking a user name and adding credit card information for payments. Follow the site's directions and sign up for an account.
Check the instructions that came with your ebook reader to make sure of the book format that it uses. There are a number of ebook formats, like Microsoft Reader, Rocket ebook, Mobisoft, RTF and others. If you don't have the right format, your reader can't read the book, so make sure that your site supports your format.
Connect the USB cable from your ebook reader to your computer. Follow the sites directions to click on and download your ebook. In about a minute, your book will be downloaded into your ebook reader, ready to read. If you have a Kindle, you don't need to use the USB cable for Amazon books, as the Kindle is wireless. Simply browse the Amazon available books listing, and click on download when you find the book you want.