I took the index with the words, transformed the range to binary, additional 3 zeros, calculated the sha256 digest, took the primary Element of the hexadecimal to transform it to binary, included a few zeros towards the 8 digits from the binary and got 00000010011 which interprets to 19 in https://bookmarksknot.com/story20491465/the-basic-principles-of-bip39-passphrase-generator