I took the index in the words, transformed the selection to binary, extra 3 zeros, calculated the sha256 digest, took the first Element of the hexadecimal to transform it to binary, additional a few zeros to your eight digits on the binary and received 00000010011 which translates to 19 in https://agency-social.com/story4606562/the-basic-principles-of-bip39-passphrase-generator