I took the index of the words, converted the selection to binary, included 3 zeros, calculated the sha256 digest, took the main Element of the hexadecimal to convert it to binary, added three zeros for the eight digits of your binary and bought 00000010011 which interprets to 19 in decimal. https://socialicus.com/story4215922/ledger-seed-phrase-bip39-no-further-a-mystery