I took the index in the words, converted the number to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Component of the hexadecimal to convert it to binary, included three zeros to your 8 digits of your binary and received 00000010011 which interprets to 19 in decimal. https://socialfactories.com/story4262980/the-ultimate-guide-to-bip39-seed-phrase-github