I took the index on the words, converted the amount to binary, additional three zeros, calculated the sha256 digest, took the very first Portion of the hexadecimal to convert it to binary, added three zeros for the 8 digits from the binary and got 00000010011 which translates to 19 in https://optimusbookmarks.com/story18762222/the-definitive-guide-to-bip39-seed-phrase