I took the index of your words, transformed the quantity to binary, extra three zeros, calculated the sha256 digest, took the primary Element of the hexadecimal to convert it to binary, extra three zeros for the 8 digits in the binary and received 00000010011 which interprets to 19 in decimal. https://bookmarkfriend.com/story19050357/new-step-by-step-map-for-bip39-english-words