I took the index from the words, transformed the selection to binary, added 3 zeros, calculated the sha256 digest, took the first Section of the hexadecimal to transform it to binary, added 3 zeros to your eight digits with the binary and acquired 00000010011 which translates to 19 in decimal. https://wavesocialmedia.com/story4426437/the-basic-principles-of-bip39-passphrase-generator