I took the index with the words, transformed the variety to binary, extra a few zeros, calculated the sha256 digest, took the first Section of the hexadecimal to transform it to binary, added three zeros for the 8 digits in the binary and received 00000010011 which interprets to 19 in https://socialbaskets.com/story4355535/the-ultimate-guide-to-bip39-seed-phrase-github