Firemonkey: How to iterate through all forms in the application using TScreen.Forms

I am attempting to iterate through the forms I have open in my application. I have found the documentation for FMX.Forms.TScreen.Forms, which looks like it can be used to accomplish my goal. However, I am confused on how I am supposed to use it.

At first I tried this in a function within my form's CPP file:

ShowMessage( Forms::TScreen::FormCount );

This produced the error 'Member TScreen::FormCount cannot be used without an object'

I figured that to mean that I need to attempt to access this property from my form, or from the global Application variable. I tried both

this->Forms...
Application->Forms...

and

this->TScreen...
Application->TScreen...

However, neither Forms nor TScreen exist within either of these objects.

How do I go about accessing Forms.TScreen.Forms?

The error gives you a clue:

Member TScreen::FormCount cannot be used without an object

TScreen is a class, not an object. FormCount is not a static member of the class, so you need an object instance of the TScreen class. And such an object is provided for you - the global Screen object:

ShowMessage( Screen->FormCount );

This is stated in the documentation:

FMX.Forms.TScreen

There is a global variable, Screen, of type TScreen, which is instantiated for use by any application with a GUI. Use Screen to obtain information about the current state of the screen in an application.

FMX.Forms.Screen

extern DELPHI_PACKAGE TScreen* Screen;