The Heliopolitan Creation Myth states that the first God was Atum. His characteristics and cult was taken over around the old kingdom time and was taken over by Re, but lived on by the names of Re-Atum and Re-Horakhte. Re-Horakhte is the rising of the sun and a falcon flying over the sky who humans was depicted with a human body, but with the head of a
falcon. The Heliopolitan Myth consists of nine gods ( The Great Ennead - AKA The Pesdjet), 1. Atum, 2. Shu, 3. Tefnut, 4. Geb, 5. Nut, 6. Osiris, 7. Isis, 8. Nephtys, and 9. Seth. Basically, the myth tells us that Atum created himself or that he rose out of the chaotic Primeval waters, and brought up a mound for him to stand on. Atum was believed to be both male and female within. So, he swallowed a seed and spat out Shu (the god of air), and sneezed out Tefnut (the goddess of moisture). Shu and Tefnut had Geb (the Earth God), and Nut (The Sky Goddess). Then, the cosmic portion of the Ennead was complete. Their children (Osiris, Isis, Nephtys, and Seth) was not considered cosmic.
The Memphite Theology was basically created to try to outdo the cosmogony of the Heliopolitan Creation Myth. The Memphite Theology states that Ptah, the main god in their religion, created the universe by using his heart and tongue. The reason that the Egyptians believed he created it with his heart and not his brain is because they believed that the heart was the main place of thought, not the brain. He brought forth every being by uttering its name, because the Egyptians believed that the name held the essence of being.
There are many more myths on how the universe was created with the Egyptians belief, but these are the main two.