Container variables?

Hi guys…

I need a way (using actionscript) to convert a circle that I draw using graphics.drawCircle ( or any object in general ) in a specific frame ( say frame 2 ) , into a symbol , and then add the symbol onto the stage on a different frame ( say frame 1)…

I was told to use container variables, but I cant find any reference to them on google… Can anyone give me some example code demonstrating how to do something like this? Thanks…