How do you script the following?

So I was just curious of anyone could explain me how I could script an inventory :)?

I mean I'm not asking for any scripts, but more on how-to-script-it and how-to-do-it.

And what I should use :)

I know for loops, Tables, functions, events, variables, and pretty much all the basics :)?

so could anyone give me a quick explenation :)?

Ty!