I took the index with the words, transformed the number to binary, additional 3 zeros, calculated the sha256 digest, took the first Element of the hexadecimal to convert it to binary, extra 3 zeros for the eight digits of your binary and acquired 00000010011 which interprets to 19 in decimal. https://funny-lists.com/story19941722/the-ultimate-guide-to-bip39-seed-phrase-github