I took the index from the words, transformed the number to binary, extra 3 zeros, calculated the sha256 digest, took the very first A part of the hexadecimal to transform it to binary, included three zeros to your 8 digits of your binary and received 00000010011 which translates to 19 https://keybookmarks.com/story19508145/the-5-second-trick-for-ledger-seed-phrase-bip39