I took the index with the words, transformed the selection to binary, included a few zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, extra 3 zeros on the eight digits of the binary and got 00000010011 which translates to 19 in https://bookmarkhard.com/story18778471/the-fact-about-bip39-seed-phrase-word-list-that-no-one-is-suggesting