I took the index on the words, transformed the quantity to binary, added three zeros, calculated the sha256 digest, took the very first A part of the hexadecimal to transform it to binary, extra three zeros for the eight digits of the binary and got 00000010011 which interprets to 19 https://wisesocialsmedia.com/story4248787/the-basic-principles-of-bip39-passphrase-generator