The reason I recommend this method is because it covers the fundamentals, and there is no need to have a local installation on your laptop. Moreover, the book will help you understand the basic concepts. If you already know the basics, trying Hortonworks sandbox is more suitable.
If you know the basics about hadoop and you can’t wait to dive in there, I recommend using Hortonworks SandBox. You may want to run the tutorials listed on their site in sequence. It’s a great way to get you started.
1- Watch the brief video on how to install Hadoop on your laptop Windows 7