A question about Christianity: How can we be sure that the bible is the word of God if it was set down by man?

I do not mean to be disrespectful but this is something I have always had trouble understanding. Humans cannot understand God, which is why we have the bible from what I understand to be able to interpret the word of God. What I’m wondering is who wrote down the words in the bible and how was he able to understand what God wanted? Did Jesus write the bible or did someone else? Did the bible just appear and get read by men? In short, how did the bible come into being and how do Christians know that what is written is the correct interpretation?

I would really like to avoid a shit-show here please. I know a good number of people on this sight don’t agree with/believe in Christianity but please keep these sentiments to yourselves. I’m not trying to pick holes in the religion, I am honestly curious about this subject.