Please help me "Vegas pro 9 question"

Okey I'll try to explain right.

You know how some people have on their video when the are at home, but it looks like they somewhere else.

Like a background behind them.

I want to know how to do it, I want to change background behind me, so it would look like I'm in a studio, or somewhere else

Any help?

pleaseeeee

Can I get an Answer plz ;(

If i understand you right, you probably need a green screen and a software to get a background looking like you are somewhere else!
Software you can use:
Sony Vegas (pro versions dont no if the cheaper versions have it)
After Effects (much more expensive)

Hope this helped you!