Actually Genesis does tell us how He created the heavens and the earth. The phrase: "and God said" is used a lot in Genesis. A christian knows that he or she has [the mirical of] eternal life because of what God has said. He speaks and it is!
If the mirical of eternal life is known because God said so - to those who believe on Christ Jesus; why is it so hard to believe that God spoke and everything was - simply because He said so? Selah...
Through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear.
Hebrews 11:3
By the word of the Lord were the heavens made; and all the host of them by the breath of his mouth.
Psalm 33:6
For he spake, and it was done; he commanded, and it stood fast.
Psalm 33:9