I took the index with the words, transformed the amount to binary, additional 3 zeros, calculated the sha256 digest, took the primary Section of the hexadecimal to transform it to binary, included a few zeros into the eight digits of your binary and got 00000010011 which translates to 19 in https://minibookmarks.com/story19587079/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting