I took the index with the words, transformed the selection to binary, additional 3 zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to transform it to binary, included three zeros to the 8 digits in the binary and bought 00000010011 which interprets to 19 in decimal. https://mysocialguides.com/story4328884/5-essential-elements-for-bip39-explained