I took the index in the words, converted the quantity to binary, included three zeros, calculated the sha256 digest, took the main Section of the hexadecimal to convert it to binary, additional a few zeros towards the eight digits with the binary and received 00000010011 which translates to 19 in https://exactlybookmarks.com/story18806143/the-definitive-guide-to-bip39-seed-phrase