I took the index in the words, transformed the range to binary, extra three zeros, calculated the sha256 digest, took the very first Component of the hexadecimal to transform it to binary, added 3 zeros to your 8 digits in the binary and received 00000010011 which translates to 19 in https://travialist.com/story9864244/the-5-second-trick-for-ledger-seed-phrase-bip39