I took the index in the words, converted the range to binary, added a few zeros, calculated the sha256 digest, took the initial part of the hexadecimal to convert it to binary, included 3 zeros to your eight digits of your binary and bought 00000010011 which interprets to 19 in https://lingeriebookmark.com/story8629967/the-basic-principles-of-bip39-passphrase-generator