I took the index on the words, transformed the number to binary, included a few zeros, calculated the sha256 digest, took the initial Section of the hexadecimal to transform it to binary, additional a few zeros for the 8 digits on the binary and got 00000010011 which translates to 19 https://telegra.ph/Unlocking-the-World-of-BIP39-A-Comprehensive-Guide-to-Mnemonic-Expressions-and-Word-Listings-01-17