I said I would read the documents of Vatican II. Let's start with the first constitution, Dei Verbum ("Word of God"). It's 26 paragraphs long, divided into six chapters. Today, I'll summarize the first half of this document.
The first chapter is on revelation. God has revealed Himself to humans, in order that humans may come to know God and share in the divine nature. God reveals himself in many ways, but the primary and most perfect way is through his son, Jesus Christ. Jesus is the image of the invisible God, seeing as they share the same nature. "To see Jesus is to see His Father (John 14:9)."
Christ's self-revelation has been preserved in two main ways. First is the apostolic tradition; Christ commanded the apostles to preach the gospel to all nations, and they did so. The apostles traditioned, or handed over, Christ's teachings and beliefs to their successors, the bishops. The Catholic Church holds onto its traditions and beliefs, which are thousands of years old, because they can be directly traced back to Christ and the apostles.
The second way God's revelation to humanity has been preserved is through the Bible. The Bible is the word of God, inasmuch as it was written under the inspiration of the Holy Spirit, who is God. It is a mistake to say, "I only follow the Bible", or "I only follow the Church". Scripture and tradition are closely linked, seeing as they have the same source, deal with the same topics, and both lead to God. "Therefore both sacred tradition and Sacred Scripture are to be accepted and
venerated with the same sense of loyalty and reverence."
Chapter Three deals with the inspiration and interpretation of Sacred Scriptures. As stated above, the Bible was written under the inspiration of the Holy Spirit. God made use of human authors to transmit his message, without overriding their free will. The authors, although they wrote about divine things in human fashion, did not corrupt their writings by adding or deleting parts of God's message. As a result, the Bible teaches "solidly, faithfully and without error that truth which God wanted put into
sacred writings for the sake of salvation."
In order to understand Scripture, a person should pay attention to things like what the author originally intended, the times and cultures the authors wrote in, and literary forms (like poetry, prophetic work, etc.). Attention should also be given to the unity of Scripture, and how Scripture relates to tradition.