Bip39 Ian Coleman. Now, at the following level we use these getting and change critical bunch to generate unique private keys. Use the above produce non-public keys and chain code and pass them to the above mentioned described function kchild = kpar + hash(Kpar, cpar, i) to make specific keys. https://techonpage.com/story4738015/bip-39-https-linktr-ee-bip39-getting-my-bip39-wallets-to-work