In my opinion God created everything. The theory that everything happened with a big bang doesn’t make much sense. A random big bang somewhere out in space doesn’t explain how humans, animals, or much of anything else was created. God wanted there to be a world, so he created the world. I can’t explain how He did this because He has the power to do many things that people can’t understand. To back up my theory, in Genesis 1:1 it states that God created the Heavens and the Earth.
Other people may believe differently, but in my mind God will always be the creator of Earth.