I took the index with the words, converted the quantity to binary, additional 3 zeros, calculated the sha256 digest, took the initial Component of the hexadecimal to transform it to binary, extra three zeros to your 8 digits of the binary and obtained 00000010011 which interprets to 19 in decimal. https://artybookmarks.com/story19429403/5-essential-elements-for-bip39-explained