Like Rob said below, start will small simple models and then slowly add the complexity. You also need to do some hand calculations to see where the thermal energy is going. That will give us an indication of how much heat is transferred at the water outlet, into the solid glass and into the air. Our first model should include only the important parts, so the hand calculations will help us identify which ones are important. (Plus we spent a lot of time learning all this in the University, we should probably use it.)
It sounds like you are using Workbench. The meshing can be in the Fluent application (Fluid Flow with fluent meshing) or in ANSYS meshing (Fluid flow Fluent) depending on the Analysis System you selected on the project page. If you use the former, the tutorial meshing step would also be helpful.
Tutorial is here: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v232/en/flu_tg/flu_tg_exhaust_manifold_cht.html
You are navigating away from the AIS Discovery experience