I took the index on the words, converted the number to binary, added three zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, additional 3 zeros on the eight digits with the binary and got 00000010011 which translates to 19 in decimal. https://bookmarkalexa.com/story4366104/not-known-factual-statements-about-bip39-explained