The Bible has many versions/editions today. They all are in essence the same, and the majority of differences are in style of language and wording. There are also some versions that are very different, and those are usually from authors/committes who are putting their own spin on the Bible. Examples of this are "The Gospel According to Jesus," by Stephen Mitchell, and the older "Jefferson Bible," by Thomas Jefferson (yes that same "founding father" Thomas Jefferson). Jefferson literally took a Bible, got out some scissors and a jar of paste, and cut out only the passages which he considered to be authentic, and put them together to make the Jefferson Bible. I've never read it, only heard about it. All in all, there are dozens of versions out there, maybe hundreds, I don't know.
For the sake of sanity, I want to use just the most widely accepted versions of the Bible when I describe it, like the King James Version and New International Version.
So here are some basics about the Bible:

It is composed of two parts: the Old Testament, and the New Testament.

There are 39 "Books" (chapters) in the Old Testament of the Christian Bible, and the same text is divided into 24 books in the Hebrew/Jewish Bible (which is called the "Tanakh"). There are 27 Books in the New Testament.

As far as religion goes, just the Old Testament is considered to be the Jewish Bible, and the combination of the Old and New Testaments is considered to be the Christian Bible. The Bible is very unique in this way- two major religions from one text.

The Old Testament is the result of a thousand years or more of oral and written history passed on. In the New Testament, people read from the Old Testament ("the Scriptures"), meaning it was already to a point where everything had been collected and written down in one document. All of this was first written down in Hebrew.

The Old Testament books all have unique histories of their own, and weren't written together, so far as I know. I suppose this is why they are called "Books" and not "Chapters."

The New Testament was written sometime from 50 A.D. to 150 A.D. (keep in mind, not all at once), in Greek. There exist about 5000 complete, partial, or fragmentary ancient manuscript copies of the New Testament- the original copies of the books & of the entire Bible have never been found.

The oldest "piece" of the New Testament that has been found is a fragment of the Gospel of John dated A.D. 120-140.

For both Testaments, the material that eventually became a part of the Bible were not the only writings of the Jewish & early Christian communities. Many of the Bible stories were retold, and imitated/altered/added to over the years. Much of the extra literature of the early Christian communities that has been found has been published as the New Testament Apocrypha. They are not regarded as having the same authenticity and authority as the Bible.

All of the texts which became the New Testament were evaluated for their believed authenticity and accuracy before they were accepted as scripture.

It is believed that by A.D. 200, 20 of the 27 New Testament books were accepted.

All of the books & words, really, of the Old and New Testaments have been analyzed & scrutinized by countless scholars, historians, and theologians for their accuracy & authenticity for many, many years. With many disagreements, I might add.
