I took the index with the words, transformed the number to binary, additional 3 zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, additional three zeros for the 8 digits of your binary and got 00000010011 which translates to 19 in decimal. https://crossbookmark.com/story18753849/new-step-by-step-map-for-bip39-english-words