I took the index on the words, converted the range to binary, additional three zeros, calculated the sha256 digest, took the first A part of the hexadecimal to transform it to binary, included 3 zeros on the eight digits from the binary and received 00000010011 which translates to 19 in https://mysterybookmarks.com/story18793329/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator