I took the index of the words, transformed the number to binary, added three zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, additional three zeros towards the 8 digits of the binary and got 00000010011 which translates to 19 in decimal. https://free-bookmarking.com/story18922497/5-essential-elements-for-bip39-explained