Powershell script and modules

Hi all, I have a question that might seem easy, but I can’t seem to find the answer.
I’ve recently read “Learn Windows PowerShell in a month of lunches” and " Learn PowerShell scripting in a month of lunches" and there’s something I never understood during my reading.

Where is located the controller script ?
It is my understanding that we should separate every tasks into separate function and bundle them into a module. I get that. But what about the controller script ? Is it also in the module ? Or in a separate script that import the module with the functions ?

Thanks,
Jacob PC

You write the controller script yourself to carry out a task; For example, a new starter script, a new VM build Script and so on.

I found a pretty good explanation here: https://community.spiceworks.com/topic/1915596-controller-script-examples.