I took the index with the words, transformed the selection to binary, extra 3 zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, included 3 zeros towards the 8 digits on the binary and received 00000010011 which translates to 19 in decimal. https://bookmarkstime.com/story20173496/the-basic-principles-of-bip39-passphrase-generator