I took the index of the words, converted the amount to binary, additional three zeros, calculated the sha256 digest, took the main part of the hexadecimal to transform it to binary, extra 3 zeros to the eight digits with the binary and received 00000010011 which interprets to 19 in decimal. https://networkbookmarks.com/story19477968/bip39-seed-phrase-mnemonics-generator-an-overview