The important thing to understand about God is He reveals Himself as one essence in three persons.God in the beginning created. The Father spoke.Jesus created. The Holy Spirit hovered over the deep. The Father oversaw it all. Jesus always existed. I AM is one of the names God reveals Himself under. The self existing one. The one who revealed Himself to Moses when the Israelites were needing a way out of Egypt.
When God became flesh in Jesus, the Holy Spirit overshadowed a young woman named Mary. The Son became flesh. The Holy Spirit dwelt inside Him to direct Him and the Father was always there to answer prayer.
That is a bit simplistic.
This ks one of those doctrines you have to believe if you are a true christian. You can't fudge on this one. It is what theologians call a fundamental. A must.