The Slingbox comes with a quick start guide, which should walk him through the entire setup process at home. He can also refer to the "Getting started with your Slingbox 500" video on support.slingbox.com for further reference.
Once the Slingbox is set up at home, all you need to do is download the appropriate Slingplayer software on whichever device you're looking to use Slingbox on.
Take a good look at this article. It should help shed some light on setting up and using a Slingbox:
Hope this helps!