I took the index with the words, transformed the amount to binary, extra 3 zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, added three zeros to your eight digits of your binary and acquired 00000010011 which translates to 19 in decimal. https://esocialmall.com/story4182243/facts-about-bip39-seed-phrase-github-revealed