I took the index in the words, transformed the selection to binary, included a few zeros, calculated the sha256 digest, took the initial Component of the hexadecimal to convert it to binary, extra 3 zeros to your eight digits from the binary and acquired 00000010011 which interprets to 19 in https://canvas.instructure.com/eportfolios/3396498/ricardooxtv236/opening-the-world-of-bip39-a-comprehensive-overview-to-mnemonic-expressions-and-word-checklists