How to use dual screen on laptop

[Azkaraoke4]

Hey everyone,
I just talked a friend into switching to hoster for his laptop. I use hoster and love it and wanted to share the experience. However when I went to one of his shows i felt so bad cause he has it set up so you can see what he is doing on the tv screen and he doesn't like that. I use a regular computer so the configuration wasn't a problem, but on a laptop I couldn't figure out how to show his desktop back ground on the second display. Can you please help me so I can help him.
Thanks