I took the index of the words, converted the variety to binary, included a few zeros, calculated the sha256 digest, took the 1st Section of the hexadecimal to convert it to binary, additional 3 zeros to your 8 digits on the binary and obtained 00000010011 which interprets to 19 in https://bookmarkpath.com/story18820436/bip39-phrase-generator-can-be-fun-for-anyone