I took the index of the words, converted the selection to binary, included three zeros, calculated the sha256 digest, took the initial Portion of the hexadecimal to convert it to binary, additional a few zeros to your eight digits of your binary and got 00000010011 which translates to 19 in https://loanbookmark.com/story18882648/getting-my-bip39-words-to-numbers-to-work