I took the index from the words, transformed the quantity to binary, added 3 zeros, calculated the sha256 digest, took the very first Element of the hexadecimal to convert it to binary, included three zeros to your eight digits from the binary and received 00000010011 which translates to 19 in https://pr1bookmarks.com/story19003110/the-definitive-guide-to-bip39-seed-phrase