Basic Belief #1 is that an invisible, intangible Person created the entire Universe.
However, the Universe by definition consists of everything that exists, which must
therefore include God. So how did this God manage to create himself?
Obviously, God exists outside the
Universe He created, so that definition needs amending to "everything except God that exists."
As to who created God, I have no idea. The Good Book says He existed since forever
We aren't told, but everything
has a cause and therefore there must have been a First Cause. God is it.
Nobody knows, but the incredibly intricate and beautiful Universe could not possibly have created itself