MC appears randomly and falls down at the Y axis and makes an animation

Hi

I have a movieclip (a raindrop), that should appear randomly on the stage at 8 different places every half a minute or so. The raindrop falls down the Y-axis and when it hits the bottom it splashes.
Only one raindrop appears at a time.

I have an allround idea what to do but how I don’t know.

I am thinking to make 8 varibles that defines the 8 places. Then some Math code to make the raindrop appear at one of the 8 places.
Then some tween to make the raindrop fall. And at the bottom I’m thinking to put an invisible button that triggers this code (or something similar)

ActionScript Code:
[LEFT][FONT=Courier New]</p>[/FONT]
[FONT=Courier New]<p>raindrop.[COLOR=#0000ff]gotoAndPlay[/COLOR]COLOR=#000000[/COLOR];</p>[/FONT]
[FONT=Courier New]<p>[/FONT][/LEFT]

when the raindrop hits the button.

Is there anyone that can help me getting on the right track to do this?

Best regards

Jost