I was trying to understand the specs on CKD function from both the bip32 standard and Mastering Bitcoin book, I couldn't understand how a private key is derived from the left side of the extended key.
The book just says the right side becomes the chain code and the left side becomes the private key, after some research online I read someone using terms like tweaks and modulus n, G which are confusing me since they were not mentioned in the book and not so much in the specification itself.
Please help me clarify on how exactly a private key is derived from the left side of output, and the relationship with all those non mentioned parts like the modulus n (Which n?), tweak (??), multiply by G ( What's G?) since all these terms are not well documented.