I took the index with the words, transformed the quantity to binary, added a few zeros, calculated the sha256 digest, took the initial Element of the hexadecimal to convert it to binary, extra three zeros on the eight digits of your binary and received 00000010011 which translates to 19 in https://bookmarkfox.com/story4583417/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting