I took the index in the words, transformed the variety to binary, included three zeros, calculated the sha256 digest, took the main A part of the hexadecimal to convert it to binary, added a few zeros to your 8 digits in the binary and obtained 00000010011 which translates to 19 https://agendabookmarks.com/story18756440/not-known-factual-statements-about-bip39-explained