Aquinas put forward 5 ways in which he believed it can prove the existence of God. The first three of the cosmological argument which consists of motion, cause and contingency. He believed that God created everything but himself. The difference between Aristotle and Aquinas is that Aristotle believed in infinite regress whereas Aquinas believed it was not possible there must have been a beginning; a first event.
The change argument Aquinas talked about is that things don’t just start