Shalom and thank you for your question! You wish to understand who is ‘telling the story’ of the Bible.

The Bible is called,  in Jewish belief, the Written Law, (the Torah) and comprises the Five books of Moses, the books of the Prophets, and other writings. These cannot be understood properly without the aid of the Oral Law. The Oral Law is mainly written down in the Talmud and commentaries that expound on the Torah according to the Thirteen Principles that were handed down by Moses from G-d. The entire Oral Law was given to Moses by G-d. We are talking about a huge body of knowledge – which actually grows constantly because as human society develops there are constantly new variables that require assessment. (For example, there is a law that we do not light fire on the Sabbath. How is that law kept in an era of electricity? Torah scholars had to arrive at a conclusion of how to keep the Sabbath both according to the letter of the law AND it’s spirit, so that we can have light, warmth, and cooked food on the Sabbath, without transgressing the above-mentioned law. Technology continues to progress, constantly bringing new quandaries.) So how can we say that all this was given to Moses on Mount Sinai? We do say it, because firstly, since Moses received the Thirteen Principles of Torah exposition from G-d and handed them down, the conclusions of a sincere Torah scholar who lives according to the Torah are considered to be a part of the Oral Law. Secondly, according to one of the accepted commentaries, Moses was granted the knowledge of the Torah as a gift from G-d, since it is so vast that a human would not have been able to learn it in time to equip the nation with it before their ascent to the Holy Land of Israel.