I took the index in the words, transformed the quantity to binary, extra a few zeros, calculated the sha256 digest, took the initial Element of the hexadecimal to transform it to binary, included three zeros towards the 8 digits from the binary and received 00000010011 which translates to 19 in https://ariabookmarks.com/story5346080/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39