I took the index with the words, transformed the variety to binary, included 3 zeros, calculated the sha256 digest, took the main A part of the hexadecimal to convert it to binary, additional 3 zeros on the eight digits from the binary and got 00000010011 which translates to 19 in https://socialexpresions.com/story4439258/5-simple-techniques-for-bip39-word-list-pdf