To the Apostles, the Canon of Scripture was given by our Lord in [Luke 24:44-45]. He spoke of "The Law, The Prophets and The Psalms". This did not include the Deuterocanonicals and is verified in later first century history by "Josephus" in his Book I Against Apion, Section VIII. The Deuts were added to the Hebrew writings in the Greek Septuagint, were never written in Hebrew, and were not even considered worthy of inclusion in the "Vulgate" by Jerome.....until he encountered pressure from Rome.
To the Apostles, the Canon was closed by Ezra and Nehemiah shortly after the return from Babylon. This was later confirmed by the Council of Jamnia when they removed the Deuterocanonicals from their Canon. The Deuts themselves were not even given full canonization by the Church until The Council of Trent.....1500 years later.
It is interesting to note what God had to say about this. Romans 3:1-2.
Since neither God in the Old Testament, nor God in-the-flesh (Jesus) in the New Testament, said, "Make a book", by your interpretive standards, the Bible itself is unbiblical.
The book of Isaiah tells us the Apostles were to bind up and seal the testimony and the law. The seventh, eighth and ninth chapters are unmistakably written about our Saviour. [Acts 17:10-11] tells us that the first century church knew what was considered scripture....and what was not. Paul says that he had great revelations [2 Corinthians 12:7] and felt the need to share them [Colossians 1:25]. He is presenting this in the form of writing.
Peter tells us [2 Peter 3:15-16] that Paul's writings have been canonized by him (Peter). Paul, on the other hand, shows the importance of keeping most of these books, scrolls and parchments together by asking Timothy to go get Mark, bringing all of Peter's letters (copies), stopping in Troas to get Paul's library, and come to Rome. [2 Timothy 4:9-13]. Since Luke is with Paul in Rome a copy of the book of Acts and Luke's gospel would certainly be available. (The Book of Acts ends as Paul's first imprisonment is ending....63 a.d.)
So.....by the time of Paul's death (68 a.d.) most of what we know to be the New Testament is in the hands of Luke, Mark and soon to be with John and guarded safely by the Greeks. Matthew is felt to have been written by about 60 a.d.; James was martyred in 62 a.d.; Jude is thought to have been written about 63 a.d.; This leaves Hebrews, the books of John and Revelation. Wherever the Apostles traveled.....copies were made. There are over 5000 Greek text copies in existence today.....obviously not all from the first century, but copies were made.
As soon as it became apparent that Jesus would not be returning in their lifetimes the Apostles got busy and began writing their Gospels and letters. Paul, himself, thought he would live to see the return.....[1 Thessolonians 4:15-16] [2Thessalonians 2:1-2] [1 Corinthians 15:51-52].....and got busy when he realized he wouldn't!
The first century Church knew what was Canon.....by at least 68 a.d., 35 years after the crucifixion.
And at least parts of the 'book' were well established before John got involved with it...
And again it's re-iterated that we shall receive life thru the name of Jesus, NOT the church...