I took the index on the words, transformed the range to binary, included three zeros, calculated the sha256 digest, took the 1st part of the hexadecimal to transform it to binary, additional 3 zeros for the eight digits in the binary and got 00000010011 which translates to 19 in decimal. https://ragingbookmarks.com/story18821908/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator