Just right-click on your circle, and select "Convert to Symbol". A popup window will appear, asking what you want to name the symbol and what Behavior to apply to it; type in a name, and select "Graphic"; the other options will be covered later, in more advanced lessons. Click "OK"; you'll see the change in your object by the blue outline surrounding it. This symbol will now appear in the Library, which you can view by pressing F11 or clicking on Window -> Library; when symbols or objects are listed in the Library, they can be re-used at any point by simply dragging them onto the canvas.
Now, let's get back to animating. On the next page, we'll create another key frame so that we can tell Flash to animate in between them.
