Getting a flash movie to STOP

Hi there...i am using Adobe Flash CS4. I am the biggest newbie with flash - i JUST wanted to create a little flash banner for an ad on google ads for my business. Google doesn't accept movies with infinite loops (must end after 30sec)...

How do i get the flash movie to stop...all mine does is make some text go small and big repetitively - NOTHING special. After 30 secs it needs to stop completely...

How can i do this...please explain thoroughly...

Thanks in advance

got it...

add a stop(); function at the end...

RESOLVED

Click on the layer you need to stop, than click F9 or go in the Window tab >> Actions. There you need to type stop(); as ARozanski all ready have said.

Just in case you use a sound, you need to put stopAllSounds() to prevent it from looping.

Best Regards.