How to install PhantomJS

I just installed Spiderable:

meteor add spiderable

Now the terminal show me this message:

spiderable: phantomjs not installed. Download and install from http://phantomjs.org/

So I downloaded the PhantomJS file for macosx but I don’t know what to do with this… There is no instructions to install it. Does anyone have an idea?

Thanks

If you are on a debian based system like ubuntu, it is as easy as sudo apt-get install phantomjs or just download and double-click install from http://phantomjs.org/download.html on windows/macosx