I took the index on the words, converted the range to binary, additional three zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to convert it to binary, included three zeros into the 8 digits in the binary and received 00000010011 which interprets to 19 in decimal. https://bookmarkmargin.com/story18834859/examine-this-report-on-bip39-mnemonic-phrase-tool