I took the index from the words, transformed the selection to binary, included three zeros, calculated the sha256 digest, took the main Element of the hexadecimal to transform it to binary, added a few zeros to the 8 digits on the binary and acquired 00000010011 which interprets to 19 in https://bookmarksoflife.com/story4378750/bip39-seed-phrase-mnemonics-generator-an-overview