I took the index in the words, transformed the number to binary, extra 3 zeros, calculated the sha256 digest, took the first Section of the hexadecimal to convert it to binary, included three zeros into the 8 digits of your binary and acquired 00000010011 which interprets to 19 in decimal. https://getsocialsource.com/story4239529/bip39-seed-phrase-fundamentals-explained