The basic thing to understand is that the description given in the Genesis regarding creation of earth in 6 days,creation of two great lights,creation of man from dust etc. was mainly meant for the people of those times when it was originally revealed ,who could readily accept these things with their available knowledge.
You are correct, the Bible is not a science textbook. And here is a little play to illustrate the point:
FADE IN:
SCENE: Inside a tent in the desert. There is a small table and chair in the middle of the tent. Some baggage is stacked at the back.
Characters: GOD invisible and omnipresent. MOSES offstage.
MOSES enters the tent.
MOSES: “What a day! If I ever see another grain of sand I swear that I am goi…”
GOD: “Moses!”
MOSES: (surprised) “Yes Lord!”
GOD: “Get pen, ink and papyrus.”
MOSES goes to the baggage and fetches a pen, ink and papyrus. He takes them to the table and sits down.
GOD: “Begin writing.”
MOSES: “Yes Lord.”
GOD: “In the beginning I created a quantum fluctuation at the hyper-sub-quark level …”
MOSES: (interrupting) “Sorry Lord. Was that spelled K-W-A-H-K?”
GOD: “Hmmm. I foresee a problem. Humans will not discover hyper-sub-quarks for another 8,726 years three months and sixteen days. Perhaps something less cosmological might work better. Moses, begin a new sheet of papyrus.”
MOSES picks up a new piece of papyrus and prepares to write.
GOD: “In the beginning I created deoxyribonucleic acid …”
MOSES: (interrupting) “Sorry Lord, but could you spell that please?”
GOD: “Oy vey! Why did I make these people so dumb?”
GOD touches a finger to Moses’ forehead.
MOSES: “Ah, now I understand. Thank you for giving me all that knowledge Lord. Unfortunately I see a problem. If I write ‘deoxyribonucleic acid’ then none of the other Israelites will know what the he… heck I have written about unless you touch all their foreheads as well.”
GOD: “Hmmm. A good point Moses. Let me think about it for a few thousand years.”
MOSES: “But what do I do while I am waiting?”
GOD: “Never mind, I have finished thinking.”
MOSES: “That was never thousands of years.”
GOD: (angrily) “Do you doubt Me! Time is Mine to command. It is subject to Me, not Me to it.”
MOSES: (humbly) “Sorry Lord.”
GOD: “Start a new piece of papyrus.”
MOSES picks up a new piece of papyrus and prepares to write.
GOD: “In the beginning I created the heavens and the earth …”
FADE OUT:
rossum