On day one (1:1-5), God created the heaven and the earth (based upon the fact that God's throne room already existed - the "third heaven" - 2 Cor. 12:2), and the fact that the "first heaven" (the atmosphere of earth was created on the second day - Gen. 1:6-8), the heaven of verse 1:1 has to be the "second heaven," or the Universe.
On day four (1:14-19), God created those things for which He "made room" on day one. "And God made two great lights; the greater light to rule the day (obviously the Sun), and the lesser light to rule the night (equally obvious - the Moon): He made the Stars also" (1:16). Based upon simple grammar, God made three distinct things. Example: I bought an apple, an orange, and I bought a banana also - an apple can not be a banana, because they are two separate things, just as, to God, the Sun is not a Star, but a unique creation. Of course, Science will tell you different.
On day two (1:6-8), God "made room" earth's atmosphere and the seas.
On day five (1:20-23), God filled those two "spaces" with the fowls of the air, and the animal life in the seas.
On day three (1:9-13), God "made room" for land animals and human kind, by separating the dry land from the seas.
On day six (1:24-31), God created animal life that dwells on either land, or land and water; He also created human kind to live on the land.
Another thing that most do not notice is that, although Adam is always known as Adam, his mate has three different names: she is called "Woman" in Genesis 2:23; she is called "Eve" in Genesis 3:20; but, her original name was "Adam" (Gen. 5:2)! That is because "Adam" is translated from the Hebrew אָדָם ('adam), which means: "man"; "mankind"; "the name of the first human being."
Based upon the innumerable, minute details found in just one chapter of the Bible,
I can just imagine how long it will take us to understand it all? ETERNITY!