I took the index from the words, transformed the variety to binary, included three zeros, calculated the sha256 digest, took the primary Portion of the hexadecimal to transform it to binary, added 3 zeros to your 8 digits with the binary and got 00000010011 which translates to 19 in decimal. https://cruxbookmarks.com/story18892143/a-review-of-bip39-phrase-list