Once you have downloaded the book in compressed zip file format, extract the book to your desktop using software like Winzip, Stuffit or your computer's built in compressed file software. In the resulting folder you will find a PDF file - this is the ebook.
PDF files can be read using Adobe Acrobat reader which is free software available from Adobe.com and typically comes pre-installed in most modern computers.
As well as the PDF file, you will also find audio files in chapter folders - these are to be used along with the ebook tutorials to help explain the topics covered in each chapter.
We have more information about extracting and transferring files in our file transfer section.