I took the index in the words, transformed the quantity to binary, extra 3 zeros, calculated the sha256 digest, took the main Portion of the hexadecimal to convert it to binary, extra a few zeros to your eight digits of your binary and received 00000010011 which interprets to 19 in https://e-bookmarks.com/story4603501/the-5-second-trick-for-ledger-seed-phrase-bip39