I took the index with the words, transformed the amount to binary, included three zeros, calculated the sha256 digest, took the 1st A part of the hexadecimal to convert it to binary, included three zeros towards the eight digits of your binary and received 00000010011 which translates to 19 in https://guidemysocial.com/story4388955/the-ultimate-guide-to-bip39-seed-phrase-mnemonics-generator