How did we get here? not just here in Nashville, but on this planet?

I hope I do not offend any of my readers.  But, if any of you believe... I mean really deep down believe the Earth was made around 6 thousand to 10 yrs ago...then I am fixing to offend you and so stop reading.
As a Southern boy , raised in the Missionary(and i do not mean the standard position) Baptist Church
in the 1960's I was taught just a part of all the above horse dung....  The earth is about 10K yrs old.... Noah and his 3 sons repopulated the earth with all its genetic diversity from about that time!!!!
Question,...... how does NOAH'S 3 sons at approximately 6 thousand BC... produce all the genetic diversity we now see amongst humans???? Let's say one of them moves over to far Eastern Europe and has all, and I mean ALL the children who are now comprising Siberia, Mongolia, Japan, China and the land bridge to North America and South America.    I know that some of you are very upset..... but, let'
just ask about Cain....you know Cain and Abel the first 4 people.... so Cain killed Abel and went over to the land of NOD..... and knew his wife,,,, really? was this " wife" his sister or another descendant of the long lost tribe of the unexplained!
What I am getting at...... is that people and I do mean all people should question things.... and ask questions?
As Christopher Hitchens once said, "That which can be accepted without proof, can be rejected without proof... "

Thanks for listening...I realize some of you will be mad about this diatribe.... well I do not care....
and question my sanity.... but guess what in 100 years we shall be gone and the question moot.