I took the index with the words, converted the number to binary, added three zeros, calculated the sha256 digest, took the initial Component of the hexadecimal to convert it to binary, extra 3 zeros to your eight digits on the binary and received 00000010011 which interprets to 19 in decimal. https://sociallawy.com/story9090098/the-ultimate-guide-to-bip39-seed-phrase-mnemonics-generator