I took the index from the words, transformed the number to binary, additional a few zeros, calculated the sha256 digest, took the first Component of the hexadecimal to convert it to binary, additional three zeros for the 8 digits of your binary and obtained 00000010011 which translates to 19 in https://lingeriebookmark.com/story8664018/the-fact-about-bip39-seed-phrase-word-list-that-no-one-is-suggesting