I took the index in the words, transformed the quantity to binary, added 3 zeros, calculated the sha256 digest, took the initial Element of the hexadecimal to transform it to binary, added three zeros on the eight digits of your binary and bought 00000010011 which translates to 19 in decimal. https://bookmarkspiral.com/story18861939/top-guidelines-of-bip39-word-list-pdf