Place the sun on the stage
Click on the scene icon in the upper left of the window.

This takes you to the main stage, out of the library.
Now you are in the main stage.
Open the library.
>Window
>Library
Now you have the main stage and the library window open.
Select the sun icon in the library window.
Drag the sun from the library window onto the stage.
Your sun is most likely too large. Remember we are adding nine planets.
Resize your sun.
Choose the free tranform too and resize it.
Now, test you move.
>Control
>Test Movie
Save your document.