I took the index on the words, converted the selection to binary, added 3 zeros, calculated the sha256 digest, took the 1st A part of the hexadecimal to transform it to binary, added 3 zeros into the 8 digits from the binary and obtained 00000010011 which interprets to 19 in https://thebookmarkage.com/story18822300/facts-about-bip39-seed-phrase-github-revealed