I took the index with the words, transformed the range to binary, extra 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, added three zeros into the eight digits of your binary and bought 00000010011 which translates to 19 in decimal. https://socialeweb.com/story4244412/ledger-seed-phrase-bip39-no-further-a-mystery