I took the index on the words, transformed the amount to binary, included three zeros, calculated the sha256 digest, took the 1st part of the hexadecimal to transform it to binary, additional three zeros to your 8 digits on the binary and received 00000010011 which translates to 19 in decimal. https://totalbookmarking.com/story19025209/the-definitive-guide-to-bip39-seed-phrase