I took the index on the words, transformed the quantity to binary, added 3 zeros, calculated the sha256 digest, took the main Section of the hexadecimal to convert it to binary, extra a few zeros towards the eight digits with the binary and received 00000010011 which interprets to 19 in https://thesocialdelight.com/story4333284/not-known-facts-about-bip39-english-words