I took the index with the words, transformed the quantity to binary, added three zeros, calculated the sha256 digest, took the initial part of the hexadecimal to convert it to binary, added three zeros towards the 8 digits from the binary and received 00000010011 which translates to 19 in decimal. https://seolistlinks.com/story21005811/bip39-phrase-generator-can-be-fun-for-anyone