I took the index on the words, converted the amount to binary, extra a few zeros, calculated the sha256 digest, took the main part of the hexadecimal to transform it to binary, included three zeros to the eight digits of your binary and obtained 00000010011 which interprets to 19 in https://nowbookmarks.com/story18934101/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator