scripting windows is easiest way how to run simple script. So I think it is suitable for this case.
The work with scripting window is easy, maybe you didn't select your model for scripting. Above of script editor is part where are all opened models. In the left part are all available, and you can move to the right part model (or more) which will be accessible in scripting window. BY default is the model accessible via variable "Model", but you can change it by inplace editor (select expression and press F2).
Output are typically to Message explorer, but there are more ways.
Another way to access model form scripting window is global object Application (See class CSApplication in Reference Guide). It has list of all opened models. So code below print names of opened models.
var Mod = Application.Models.GetObject(i);
BTW: You can find property ActiveModel of Application, but when you are in scripting window, there is no active model. This property is possible to use in macros or other, but not in scripting window.