I took the index on the words, converted the range to binary, additional 3 zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to transform it to binary, additional a few zeros towards the 8 digits with the binary and got 00000010011 which translates to 19 in https://bookmarksfocus.com/story4380114/facts-about-bip39-seed-phrase-github-revealed