Hello dARKTOILET,
If you copy&paste a test case multiple times you will create test cases that have a different name but still refers to the same modules. Therefore, when you then go into one of the copied test cases and make changes in the modules this changes will reflect in all other test cases and you effectively end up with all test cases the same again
In order to provide you with some adequate advice the forum community will have to know the following:
1. Have you already considered data-driven testing? If the differences between your test runs are mainly values of variables then this is your solution. In this way you could keep only one test case.
Lesson 3: Data-Driven Testing
2. Can you explain in more detail what the differences between your test cases should be? Maybe someone will come up with a good suggestion.
The recommended way would be to create modules that contain actions that are repeated in all test cases and modules that are test case specific. After that you should arrange them into the appropriate test cases. This enables for maximum re-usability and a good overlook for when something goes wrong.
Regards,
McTurtle