If the mentioned guide is anything to go off of, it looks like you just need to set up BitTorrent-Sync with the right information (the config provided from Raz should get you started, but you may need to modify your file paths. I don't use OSX, but it shouldn't be too different from Linux, they are both unix-likes.) and run it.
I would guess this is a good place to pick the software up (with instructions + their official website):
http://macappstore.org/bittorrent-sync/There are a lot of third party places though.
I am of course assuming the OSX bittorrent sync is very like the linux one.