I took the index from the words, converted the quantity to binary, added 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to convert it to binary, additional a few zeros towards the 8 digits of your binary and obtained 00000010011 which interprets to 19 in https://mnobookmarks.com/story18747384/the-definitive-guide-to-bip39-seed-phrase