I took the index in the words, converted the selection to binary, added three zeros, calculated the sha256 digest, took the 1st Component of the hexadecimal to convert it to binary, additional a few zeros to your eight digits of your binary and received 00000010011 which translates to 19 in https://wiishlist.com/story19448616/a-secret-weapon-for-bip39-words-to-numbers