How do one day simulator courses work?
I’ve done one of these before (not with that company). It literally used the Microsoft FSX game engine but with an A320 cockpit. You have an instructor guiding you and I got to fly around my local airport, land at Kai Tak at night (nailed my first attempt), and because I was in real-world training at the time I shot an ILS approach in zero visibility (definitely did not nail that one). 

These simulators are usually aimed at people with little to no piloting experience who want some fun (and they are, I enjoyed mine and my dad has done it 3 or 4 times). If you’ve used FSX you know that you can adjust the realism settings to make it easier to fly so, with help from the instructor a novice can probably land it. At the very least you will learn about basic procedures, flaps etc, and what the cockpit looks like.

It will definitely not make you ready to land the real thing though. These things are designed for fun, not realism.