I took the index in the words, transformed the selection to binary, additional three zeros, calculated the sha256 digest, took the initial A part of the hexadecimal to convert it to binary, additional three zeros on the 8 digits on the binary and obtained 00000010011 which interprets to 19 in https://postheaven.net/tiablexcen/mastering-your-copyright-protection-the-essential-overview-to-bip39-passphrases