Does anybody know how to make a Boolean search?

If you go to and do a keyword search on "homes for sale" you will see that it brings up a bunch of schools and other unrelated stuff. I'm pretty sure it's because of the word "for" as I don't have Boolean search capabilities just yet?

Anybody know of any Boolean search tutorials? I want the ability to search with "+" "and" "for" and " ".

Any help would be appreciated. Thanks a ton.

The code is here: