I took the index on the words, converted the range to binary, added 3 zeros, calculated the sha256 digest, took the first Section of the hexadecimal to convert it to binary, additional 3 zeros to your 8 digits on the binary and bought 00000010011 which interprets to 19 in decimal. https://bookmarkinglive.com/story19839342/fascination-about-bip39-english-words