I took the index on the words, converted the selection to binary, additional three zeros, calculated the sha256 digest, took the very first A part of the hexadecimal to transform it to binary, included three zeros to your 8 digits of your binary and bought 00000010011 which translates to 19 https://sites2000.com/story8438947/an-unbiased-view-of-bip39-seed-phrase-github