I took the index with the words, transformed the selection to binary, included a few zeros, calculated the sha256 digest, took the main part of the hexadecimal to convert it to binary, additional three zeros to the eight digits of the binary and bought 00000010011 which translates to 19 in https://altbookmark.com/story20445130/the-2-minute-rule-for-bip39-all-words