Ansys Employee

No worries, good to see you started with the tutorials. Too many don't. 

OK, it looks like you've not quite got it right. Fluent needs telling it's a multiphase model, so have a look at the options (Learning & Help) to help choose the right one. Also look up temperature dependent properties and buoyancy. When you are looking at the models you also want to consider what you need to know from the results, and what else you may want to know later on: we use models for specific functions so need to know ahead of choosing the starting point. Set up is fairly easy, working out what to set up is the hard bit. 

I also suggest looking at "thin walls" in Fluent as you generally don't mesh the container unless there's a very good reason.