I took the index with the words, converted the amount to binary, included three zeros, calculated the sha256 digest, took the first Element of the hexadecimal to convert it to binary, included 3 zeros towards the eight digits of your binary and acquired 00000010011 which translates to 19 in decimal. https://www.slideserve.com/lewarthbfp/bip39-word-list-explained-your-essential-source-for-creating-secure-purses-in-t