Create a MovieClip in Main and a custom Class for it
I do realize than many developers like to add MovieClips dynamically to the stage and here I am adding them physically. If you want to add them dynamically follow the process that I show you and then just delete them. You can add them to the stage later dynamically and control them through Main as they will have their linkage (in case you don't know, linkage makes a MovieClip in the library assessable to ActionScript).
Okay, so drill into Main and use your text tool to create a static textField with the text value of TestObject, yeah, I know, very creative naming convention.
Now select TestObject and hit F8 to turn it into a symbol with a name of TestObject and an instance name of testObject (*** NO CAP T**). Now select it in the library and click the new Class Icon in gProject. Make the package name com.rezn8.ui.TestObject (ui is for User Interface).
Make sure to select open, bound, etc, etc,
Now gProject makes our custom Class for us, builds the directory structure and organized our library.
Now, we want Main to control TestObject, right? Well it cannot yet but if you go onto the last section I will show you how you can. Excited? Yeah, me too...