I took the index of your words, converted the selection to binary, additional a few zeros, calculated the sha256 digest, took the initial Section of the hexadecimal to transform it to binary, included three zeros to the 8 digits of your binary and received 00000010011 which interprets to 19 in https://techonpage.com/story4384516/bip39-seed-phrase-mnemonics-generator-an-overview