I took the index with the words, converted the number to binary, extra three zeros, calculated the sha256 digest, took the very first Element of the hexadecimal to transform it to binary, added 3 zeros for the 8 digits of your binary and received 00000010011 which interprets to 19 in https://orangebookmarks.com/story19531670/the-definitive-guide-to-bip39-seed-phrase