Those three concepts set a clear framework from which speakers and writers can more effectively connect with their audiences.
Logos is using logic to persuade people. "We should walk out of this movie because our marginal utility functions provide sufficient reason to seek enjoyment in another theater."
Ethos uses ethics or morals to explain. "We should walk out of this movie because there's is something fundamentally wrong with sitting in a movie that you don't like. It's just wrong."
Pathos is using emotion to persuade. "I'm going to cry if we don't leave this movie. You don't want me to start wailing right here, right now, do you?"
The great speakers of the world, use the best combination of these three techniques to get their message across. Now you can too!