I set this up today at long last (and assume most of it will apply to Box as well). Couldn't find much use on how to actually make it sync, so here is a picture!
Go into your Preferences -> Cloud sync settings; and enable dropbox. You can go into Dropbox Settings to control stuff like what to sync and where to sync, etc. Then go to the "Schedules" tab and voila!
I don't see what is so schedule about that, and I seem to remember reading that you have to do sync's manually rather than on a schedule but whatever. Couldn't find crap on Google, so I took a screenie ^_^.