I took the index on the words, converted the number to binary, additional a few zeros, calculated the sha256 digest, took the main part of the hexadecimal to transform it to binary, additional 3 zeros towards the eight digits on the binary and got 00000010011 which interprets to 19 in https://sites2000.com/story8570496/facts-about-bip39-seed-phrase-word-list-revealed