Almost all computers nowadays can easily open compressed (zipped) folders.

To open the compressed (zipped) folder, simply click or double-click, depending on how your computer is set up, on the folder's icon. If any additional steps are required to open the folder, your computer should notify you of such.

Should, on the off chance, you need a special utility to open it, you can get one for FREE at:

http://www.7-zip.org

Note: This article only applies to those ebooks/ebook packages packaged in compressed (zipped) folders.