I took the index from the words, converted the amount to binary, additional a few zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, added three zeros to the 8 digits from the binary and got 00000010011 which translates to 19 in https://bookmarkbirth.com/story18874106/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting