Open rocket.fla
Open the library and you will see two graphic symbols rocket and flame.
Select insert new symbol and give it a name rocketBT and type button, then press ok.
On the rocket timeline in the up state drag a copy of the rocket to the cross in the middle of the stage. Use the free transform tool to rotate it around so it is facing straight up. Return to Scene 1.
Select insert new symbol and give it a name rocketMC and type Movie Clip.
On layer 1 frame 1 as before drag a copy of the rocket to the cross in the middle of the stage. Use the free transform tool to rotate it around so it is facing straight up. Then insert a frame on frame 5, next create a new layer.
Drag a copy of the flame from the library and place it on frame 1, again rotate the flame so it is underneath the rocket. Insert a key frame at frame 5 and then use the free transform tool to make it slightly larger. Next select frame 1 and open the properties panel and select motion tween to animate the flame.
Now you have completed the animation return to buttons timeline, insert a keyframe in the over state and drag a copy of the movie clip to the cross in the stage. Select the hit frame and press F5 to insert a frame.
Return to the stage a drag a copy of the button to the stage, control / test movie to see your animated button.