I took the index in the words, transformed the quantity to binary, extra three zeros, calculated the sha256 digest, took the initial Element of the hexadecimal to convert it to binary, extra a few zeros to your eight digits in the binary and obtained 00000010011 which translates to 19 in https://bookmarkspecial.com/story19771657/the-ultimate-guide-to-bip39-seed-phrase-github