Newbie Needs Help-hide/show object


I just began to use Flash CS3, so I am learning the most basic skills, using tutorials. I am trying to create a basic animation: the scene would have 2 white circles, one on each side of the screen, left and right. Each would display for .5 seconds while the other is hidden, and these show/hide actions would alternate for a 30 second movie.

I’ve set each of the 2 circles on a different layer and moved them to the stage, having converted each one to a movieclip. I have tried to script each circle/movieclip using .visible=false type script, but this doesn’t work. I keep getting syntax errors.

I have not been able to find a very basic tutorial to show a new user how to create 2 circles that can be alternately (one, then the other)shown/hidden, .5 seconds each for 30 seconds total.

I am hoping someone can provide a very basic walk-through, step-by-step for someone who knows almost nothing about Flash.

Or, if someone can suggest a tutorial.

Thank you for any help.

Kind Regards,