You use than to compare, whereas then is used more generally an indicator that something comes later in some sense (temporally for the result situation). For example, "Edison is better than a panda," and, "The best things ever are Edison then pandas," or also, "I will impress Edison, then I will pet a panda." Someone else should probably explain, though, due to my insistence on the panda theme here, which may confuse... and I'm too lazy to fix it....