I took the index in the words, transformed the selection to binary, additional a few zeros, calculated the sha256 digest, took the main Section of the hexadecimal to transform it to binary, added a few zeros to the eight digits of your binary and obtained 00000010011 which interprets to 19 https://mnobookmarks.com/story19399594/ledger-seed-phrase-bip39-no-further-a-mystery