What did greek gods represent?

They represented a way to explain life. I.E. lightning strikes because Zeus, king of the gods and the sky, is striking down an opponent, or the sun rises because Apollo rides his sun chariot across the sky, making the sun move across the sky. As to explain life itself through the Greek Gods, the essence of life was born from Chaos: the Earth (Gaia), the sea, day (Hemera), night (Nyx), the underworld (Tartarus, better known as Hades), and Love (Eros, AKA Cupid). From these things, everything else was reproduced from Mother Earth.