The scripts will be converted into code injections. So you need to know what code injections are and how they work. Code injections just injects (write) own code into another process memory (simplified).
For a code injection to work you need to know where it should inject the code and what code should be injected. This requires basic assembly language knowledge.
To figure out the 'where' you need a debugger and for example the searched value for health. Then set a breakpoint on that address. The debugger will now break as soon as the value was accessed by a function of the game. It will also show you the exact location of the part of the function.
This part of the function of the game you can use for your code injection (if it is not shared). Next you need to know what the (opcode) of the function is doing. Then you get an idea what you need to modify the code.
A classic code injection for health would work this way:
Take the function that accesses the player's health and everytime it is accessed write a value of 100 to player's health.
This may sound extremely complex. But it stand and falls with your knowledge of assembly. Also a bit of programming experience can help. Once you can read and understand assembly, the code injections are (in combination of the scripts that require zero programming experience) super easy.
I've demonstrated that you can create such a script within 2 minutes for the game Starbound. If it is not a demonstration it can even be done in less time.
You can find the video here:
Link