I took the index in the words, transformed the variety to binary, added three zeros, calculated the sha256 digest, took the main Portion of the hexadecimal to transform it to binary, added three zeros for the 8 digits with the binary and bought 00000010011 which translates to 19 in decimal. https://artybookmarks.com/story18691594/5-essential-elements-for-bip39-explained