In the beginning was the Word, and the Word was with God, and the Word was God.
John 1:1
The beginning of Genesis and of the gospel of John, we read the words, “In the beginning.” There are not two beginnings, nor will there be two ends. The one beginning the Bible speaks of is creation. Obviously God predates that beginning because He is the un-created Creator. Before He created anything else, God has always been.
Everything else that exits, exists because God created all things.
Why does John begin by looking back at the beginning? Because the Word (Jesus) was with God in the beginning because Jesus is God. All three Members of the Trinity: Father, Son and Holy Spirit are the One true and living God and are the Creator of all things.
God plan for creation included humans, who would sin. That same plan for creation included God’s plan for salvation (forgiveness) of sinful human beings by Jesus.
Though the Bible is divided into two Testaments containing sixty-six books, it is one book. It is one story about the One true and living Creator God, who is also the One and only Savior God. The entire Bible is about Jesus.