1 In the beginning God created the heaven and the earth.
2 And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
3 And God said, Let there be light: and there was light.
And this is the evidence.
Click!
I think the story out of the Bible tells it all. It just takes some people a long time to believe that information. The exact methods used is not explained of course, but just know that God says he caused it to be. If a person can believe that, then it goes a long way toward making the rest of the marvelous creation story believable. Disbelieve it & little else in the Bible will make sense.