I am a biochemistry major entering my freshman year, and I have no idea how DNA works, and I'm convinced most people, if not everyone, has no idea how DNA works.

Yeah sure I get translation, transcription, sugar phosphate, purines and pyrimidine, but heres some facts:
3.2 billion base pairs in the human genome
~25000 genes
60% of human DNA is the same as a banana
98.8% of human DNA is the same as a chimp
We know that traits like intelligence are somewhat genetic
How the fuck does a protein influence that? What the fuck is going on? HOW DOES THIS HAPPEN I DONT FUCKING UNDERSTAND ITT
AND ITS 3.3 GB !? the entire human genome is 3.3 gig, how? JElly fish genome size is 0.3gb

And then they say OH OK cells differentiate because they can turn on and off gene expression. Ok so a protein must have to do that ? i just -
this shit is fucking insane and I feel like everyone is just pretending to know what theyre talking about.

Please help me understand DNA and genetics... This shit drives me nuts.