Bip 39 index https://zenwriting.net/keenanctdp/how-to-create-a-bip39-seed-a-step-by-step-guide It is very important which the mnemonic sentences are produced from randomly selected numbers! These quantities can be created in a number of alternative ways, that happen to be described in other content articles right here, like "Exactly what is an RNG" and Seed Phrase Era. https://linktr.ee/bip39