I took the index in the words, transformed the range to binary, extra 3 zeros, calculated the sha256 digest, took the primary part of the hexadecimal to convert it to binary, added three zeros for the 8 digits of your binary and bought 00000010011 which translates to 19 in decimal. https://social-lyft.com/story9025396/considerations-to-know-about-bip39-seed-phrase-generator