I took the index with the words, converted the quantity to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Component of the hexadecimal to transform it to binary, included 3 zeros for the 8 digits of your binary and acquired 00000010011 which interprets to 19 in decimal. https://myfirstbookmark.com/story19633443/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool