I took the index on the words, transformed the range to binary, additional 3 zeros, calculated the sha256 digest, took the primary Element of the hexadecimal to convert it to binary, added 3 zeros to your eight digits of the binary and obtained 00000010011 which interprets to 19 in decimal. https://fellowfavorite.com/story20006421/considerations-to-know-about-bip39-word-list-pdf