I took the index from the words, converted the range to binary, included three zeros, calculated the sha256 digest, took the initial Component of the hexadecimal to transform it to binary, extra a few zeros for the 8 digits from the binary and got 00000010011 which translates to 19 in https://bookmarkmargin.com/story18807195/bip39-seed-phrase-mnemonics-generator-an-overview