I guess that z and z' has the same meaning as in this Wikipedia article. If so, then z is simplified transaction hash. All you need to do is just calculate SHA-256(simplified_transaction) and that will be your z. The same for z', it will be just another simplified transaction signed using the same k value. Here you have two inputs, so for each of them you should create two different simplified transactions. Here is some example.
it is not "simplified", the transaction is instead "modified" and it is a complicated process. and the example you shared like many others on SE are only covering a small portion of the entire difference cases so they only work for that special case which is usually spending a legacy P2PKH output with SIGHASH_ALL.
FWIW starter doesn't seem to communicate back at all. he already has another duplicate of this topic in another board and also asking the same 2 questions on SE.
