I took the index in the words, transformed the number to binary, added three zeros, calculated the sha256 digest, took the initial A part of the hexadecimal to convert it to binary, additional three zeros towards the eight digits from the binary and got 00000010011 which translates to 19 in https://royalbookmarking.com/story18814164/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool