I took the index from the words, converted the number to binary, added 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to convert it to binary, additional three zeros towards the 8 digits on the binary and obtained 00000010011 which translates to 19 in decimal. https://exactlybookmarks.com/story18789623/bip39-phrase-generator-can-be-fun-for-anyone