I took the index of the words, converted the amount to binary, added three zeros, calculated the sha256 digest, took the very first Component of the hexadecimal to convert it to binary, included 3 zeros into the 8 digits from the binary and got 00000010011 which translates to 19 in https://bookmarkprobe.com/story19067471/not-known-factual-statements-about-bip39-explained