I took the index of your words, converted the number to binary, added 3 zeros, calculated the sha256 digest, took the main Element of the hexadecimal to convert it to binary, included three zeros to your 8 digits from the binary and acquired 00000010011 which interprets to 19 in decimal. https://bookmarkfriend.com/story18849265/bip39-seed-phrase-mnemonics-generator-an-overview