I took the index in the words, transformed the amount to binary, additional 3 zeros, calculated the sha256 digest, took the very first Section of the hexadecimal to transform it to binary, added three zeros to your 8 digits on the binary and obtained 00000010011 which translates to 19 in https://bookmarksea.com/story19001152/considerations-to-know-about-bip39-word-list-pdf