I took the index with the words, transformed the range to binary, extra 3 zeros, calculated the sha256 digest, took the primary Portion of the hexadecimal to convert it to binary, added three zeros towards the 8 digits in the binary and received 00000010011 which translates to 19 in decimal. https://freshbookmarking.com/story18850841/a-review-of-bip39-passphrase