I took the index with the words, transformed the quantity to binary, extra three zeros, calculated the sha256 digest, took the primary Element of the hexadecimal to transform it to binary, included 3 zeros into the eight digits on the binary and received 00000010011 which translates to 19 in decimal. https://icelisting.com/story19833742/the-ultimate-guide-to-bip39-seed-phrase-github