Getting started with SASS on mac.

I am just getting started with SASS (and PHPStorm) and I kind of feel stuck with the setup of SASS right now.

I am trying to follow: http://www.jetbrains.com/phpstorm/webhelp/transpiling-sass-less-and-scss-to-css.html

so far I have installed SASS using the terminal of mac (very quick and easy btw) and I have setup a Watcher in PHPStorm with the base information (I did not change anything). I see nothing happening when trying to work with the .sass file and I wonder if it's because of a misconfiguration of the path variable cause I did not know what to put that really...

Any help is much appreciated :)