I took the index in the words, converted the range to binary, additional three zeros, calculated the sha256 digest, took the initial A part of the hexadecimal to transform it to binary, added a few zeros towards the eight digits of the binary and got 00000010011 which translates to 19 https://thesocialintro.com/story4367988/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator