(Again, if you read the bible its pretty clear what God is going to grade us on.)
The Bible is very clear about salvation. The New testament is devoted to Christ teachings. Creation in Genesis is limited to 37 sentences in Chapter one, and one very long sentence in chapter two. There is a lot of room for interpretation. I believe that if we were to be judged on whether our interpretation is correct or not, it would be far more detailed. The point of Genesis is that God did it, and we should have faith in that. How, is not spelled out.
( The bible (NT) can be traced back to the original texts which were written, in many cases, by the witnesses of events.)
There was no original witness to creation other than the Creator. Authorship of Genesis is thought to be attributed to Moses. I believe the Bible to be God's inspired word. Moses would have to have been inspired through some sort of revelation, perhaps a vision or a dream. What would this have looked like? If the Earth, and life took many years to form, would the vision have reflected that, or might it have been interpreted spontaneously? One thing I find very curious in Genesis is that on four occasions it mentions life being formed out of the Earth. What did Moses see in his revelation that he would interpret in this way?
Maybe God inspired Moses on what to write. After all, the Bible is the inspired word of God. And Genesis is clear that God is the creator of all.
In John 5:46-47, Jesus says: "If you believed Moses, you would believe me, for he wrote about me. But since you do not believe what he wrote, how are you going to believe what I say?"
What did Moses write about Jesus?
And...There are several references to creation outside of Genesis chapters 1 and 2, including New Testament references (a few by Jesus).
How, is not spelled out.
Yes it is...He spoke it into existence (Genesis 1; Hebrews 11:3).