Hi,
You can access your system analysis tool on the Analyze tab > Energy Optimization Panel > System Analysis. Please refer to attached image.
If you are missing this tab in your Revit software, you may have to enable it. To do so, navigate to File > Options > User Interface and you will see "Configure tools & analysis" at the top of the dialog box. I have attached an image of this for you.
With regards to heating and cooling loads, have a look at this resource.
Hope this helps, have a great day ahead 🙂
