Read the Bible from start to finish.
I mean it.
Start at Genesis, chapter 1, verse 1 "In the beginning God created the heaven and the earth." and slog your way verse-by-verse through the Hebrew Bible to Malachi 4:6 "And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.", and on through Matthew in the New Testament "The book of the generation of Jesus Christ, the son of David, the son of Abraham." to Revelations 22:21 "The grace of our Lord Jesus Christ [be] with you all. Amen."
If you're feeling studious, write a note or two on each chapter. Regardless, you will probably not get far before you say to yourself "there's something wrong with this".
You might even stop at Gen 1:1 and ask yourself "who is this 'God' and where does he get this heaven and earth-creating power?". It's conceivable that you could get a bit pickier and ask "what beginning, what heaven?". Then, you'll write a note to yourself to see if this God guy is explained, where he came from, how he got his powers. Maybe a few clearer definitions will be offered, so that you get a sense of whether this guy is worthy of further attention.
By the end of Genesis 1, you'll no doubt have noticed how backward God works ... Or how backwards the author got it. He's creating earth and grass before he creates the sun and moon; he creates man "in our image" - even tho' no one can explain why God needs a peepee or a vajayjay ... Let alone why man and woman would be in their (or his) image in the first place. Extra credit: look for the chapter in the Bible that explains why he refers to himself as "in our image" - as if he's a group. Alternatively, how do male and female both come from his image? Did he have male and female junk?
Then he makes man (and woman) again in Chapter 2.
My favorite stuff is in chapters 6 through 9 - Noah's Ark. Try to figure out how that worked ... You'll have fun.
It goes on and on and on like this.
I dare you to read it.