I took the index on the words, transformed the amount to binary, added three zeros, calculated the sha256 digest, took the 1st Portion of the hexadecimal to transform it to binary, additional 3 zeros to your eight digits with the binary and bought 00000010011 which translates to 19 in decimal. https://ezmarkbookmarks.com/story18936038/bip39-phrase-generator-can-be-fun-for-anyone