Where should i start my study of greek philosophy?

I feel the need to have a decent knowledge of classical greek philosophy (Socrates, Plato, Aristotle, etc) where should I start. I am in the middle of taking a class that surveys classical Greek and Christian philosophy, and I know there are plenty of pre-Socratic philosophers but I don’t want to waste my time learning something that isn’t beneficial. So at what philosopher should I stop taking overviews and begin reading the real stuff? Also should I read **everything** by Plato and Aristotle? Should I do it chronologically? If you know of a good collection of works I would like to know about it