I took the index in the words, transformed the quantity to binary, extra 3 zeros, calculated the sha256 digest, took the first Element of the hexadecimal to convert it to binary, extra three zeros for the 8 digits on the binary and got 00000010011 which translates to 19 in decimal. https://businessbookmark.com/story4465292/5-essential-elements-for-bip39-explained