I took the index from the words, transformed the quantity to binary, extra a few zeros, calculated the sha256 digest, took the initial Section of the hexadecimal to convert it to binary, included three zeros to your eight digits of your binary and received 00000010011 which interprets to 19 in https://bookmarkcork.com/story19584313/the-ultimate-guide-to-bip39-seed-phrase-github