There were different "beliefs" among Greek philosophers.
The main ones were:
1. Earth was the centre of the universe and everything was going around Earth (even if some planets needed epicycles to explain parts of their movements).
2. The Sun was the centre and Earth orbited around the Sun.
2a. Everything else was going around the Earth, or
2b. The Moon was going around Earth, but the other planets were going around the Sun (2b is the closest to the modern understanding),
and, you could probably find some people who used a mix (for example, Mercury and Venus around the Sun, other planets around Earth).
3. There was a central fire. The Sun and the Moon were mirrors that reflected the light (and heat) from the central fire. Earth was a cylinder and we lived on the face of the cylinder that kept pointing away from the central fire (When the Greek started to travel up and down the Nile River and noticed the change in the tilt of the sky, this idea died off).
Aristotle was the most influential of the philosopher, and he kept preaching number 1, so it eventually won out. The written version (by Ptolemy) survived until the modern times, as it had been saved (and translated, and updated) by Arab astronomers.
But you question is when did they "learn" about any of these, and that is not known. All three versions existed (in some form) in Babylonian astronomy, before the Greeks (the Greeks inherited most of their astronomy from the Babylonians).