I took the index with the words, transformed the amount to binary, extra 3 zeros, calculated the sha256 digest, took the first Element of the hexadecimal to convert it to binary, added 3 zeros to the 8 digits with the binary and received 00000010011 which interprets to 19 in decimal. https://express-page.com/story4189137/little-known-facts-about-bip39-words