Convert Object to Symbol
Flash CS3 Tutorial
How to Convert a Flash Object to a Movie, Graphic or Button Symbol
A common way to create symbols is to start with an object, then convert it to a symbol.
You can also start with a new empty symbol, add content to it, and then drag it to the stage. For information on the second method see topic, Insert New Symbol.
Add a rectangular object to the workspace with the Rectangle tool (r key).
With the rectangle selected, press F8 (Modify > Convert to Symbol).
In the dialog box, name your symbol and choose the symbol type (Movie clip, Button, or Graphic).
The dialog box also lets you set the symbol's registration point. The registration point is used as a pivot point in ActionScript when rotating and scaling. It is also used set the object's location on the stage.
Once you have created a symbol, double-click the symbol with the Selection tool (v key)to open the symbol timeline.