I took the index from the words, converted the range to binary, included a few zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to convert it to binary, added a few zeros on the eight digits with the binary and bought 00000010011 which translates to 19 https://zanybookmarks.com/story18902877/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool