I took the index from the words, converted the selection to binary, added three zeros, calculated the sha256 digest, took the first part of the hexadecimal to transform it to binary, included three zeros to your eight digits on the binary and bought 00000010011 which interprets to 19 in decimal. https://iowa-bookmarks.com/story14476279/new-step-by-step-map-for-bip39-english-words