I took the index with the words, transformed the quantity to binary, extra three zeros, calculated the sha256 digest, took the 1st A part of the hexadecimal to convert it to binary, additional 3 zeros to your eight digits of your binary and bought 00000010011 which interprets to 19 in https://bookmarklayer.com/story18842402/bip39-phrase-generator-can-be-fun-for-anyone