I took the index in the words, transformed the quantity to binary, additional 3 zeros, calculated the sha256 digest, took the main A part of the hexadecimal to transform it to binary, extra 3 zeros into the 8 digits with the binary and obtained 00000010011 which translates to 19 in https://total-bookmark.com/story18908919/bip39-seed-phrase-mnemonics-generator-an-overview