I took the index with the words, converted the selection to binary, added a few zeros, calculated the sha256 digest, took the 1st part of the hexadecimal to transform it to binary, added 3 zeros for the 8 digits of the binary and got 00000010011 which translates to 19 in https://bookmarkproduct.com/story18957706/bip39-seed-phrase-fundamentals-explained