The Bible doesn't say that you shouldn't edit or correct the Bible because the authors of the Bible didn't have the rest of the Bible.

Moses gives some explicit commands to the Israelites to not modify the commands he gives in Deuteronomy, but that doesn't really apply to the other books.

Likewise, some guy named "John" warns against anyone adding or removing from the account of his acid trip in Revelations, but that doesn't really apply to other books.

The "Bible" was constructed over a long process and while what many think of as the "Bible" was finalized by 400AD there are still disagreements today (See Judaism, Catholicism, Protestantism, Pentecostalism, Mormonism, and many other smaller sects).

The original authors wrote disparate works for distinct purposes at distinct points in time. They were not writing with the goal of manufacturing a multi-thousand year story bound as a single volume.

How do we know the full story?

We don't. We use archeology, biology, anthropology, and other scientific disciplines to determine a likely path of the story of humanity as a whole. Some disciplines use the books of the Bible and other contemporary accounts to guide areas of future study, but if you want a single source for the history of the earth, humanity, or even the Israelites the Bible isn't going to offer an honest perspective.