I took the index in the words, transformed the quantity to binary, included three zeros, calculated the sha256 digest, took the 1st Component of the hexadecimal to convert it to binary, extra three zeros to your eight digits of the binary and acquired 00000010011 which translates to 19 in decimal. https://seolistlinks.com/story20387645/bip39-seed-phrase-mnemonics-generator-an-overview