If you wanna make a simple aimation with a play button,first,open up Flash MX and make 2 scenes. Now,on the first scene make your play button, design it anyway you please. Now use the black cursor at the left hand side at the top and highlight your button. Now that you have everything highlighted right click it somewhere and a menu should come up on the side. Go down towards the bottom and click 'convert to symbol' and then something else should pop up. It will ask you if you wanna turn it into a movie clip, button, or graphic. Click on button and hit OK. Press F1 or go down to the bottom and hit the thing that says "Actions-Button". For the button type in the code below:

on (release) {
play();
}

The on (release) part of the code means,that when you click on the button and then release it will play the movie,and thats where play(); comes in! Now go to your second scene,make your animation,if your not sure about how to make a picture for each keyframe I'll tell you about that in the next section!

Keyframes And Animation

First,look at your timeline,it has little keyframes in it.Click on your first keyframe and draw whatever you want. Now right click the next keyframe and make the changes you want in that picture then right click the next and make some changes and so on. Until you have the animation you want. Now save your animation as a .fla as 'my coolest animation'.Now go up to the top where it says controls and click 'test movie',so you'll first see your button,click on your button and then you'll see your animation,now your done.