I took the index of your words, transformed the amount to binary, added a few zeros, calculated the sha256 digest, took the first Section of the hexadecimal to convert it to binary, additional three zeros on the eight digits on the binary and received 00000010011 which translates to 19 in https://dmozbookmark.com/story18839089/the-ultimate-guide-to-bip39-seed-phrase-github