I took the index from the words, transformed the range to binary, additional three zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to transform it to binary, additional three zeros to your 8 digits in the binary and got 00000010011 which translates to 19 in decimal. https://push2bookmark.com/story19299927/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39