I took the index in the words, transformed the quantity to binary, extra three zeros, calculated the sha256 digest, took the 1st part of the hexadecimal to convert it to binary, additional a few zeros on the eight digits from the binary and obtained 00000010011 which translates to 19 in https://bookmarksknot.com/story20741497/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool