I took the index in the words, transformed the amount to binary, extra three zeros, calculated the sha256 digest, took the main A part of the hexadecimal to transform it to binary, added three zeros to the 8 digits of your binary and bought 00000010011 which translates to 19 in https://pukkabookmarks.com/story19092545/an-unbiased-view-of-bip39-seed-phrase-github