Where the heck do I put my ActionScript Code?

So in my first study, I'm going through the first example in the book "Flash Math Creativity" called "TowardUs" by Jamie McDonald. Jamie does a good job explaining that we should get familiar with the sin and cos trig functions because they're good for making oscillating movement. Ok, cool I'm with you so far. The example creates a bunch of small little balls that spin and grow and then fade away when you think they're about to hit you in the face. Awesome, how do I do it?

Here's where it went down hill. In the book he talks about adding Ball movieclip then adding a another movieclip called Events within that movieclip that contains actionscript as such:

onClipEvent (enterFrame) {
_parent.myfunct();
}

erm... wha? Why am I doing this... what's going on? Where does this snippet go now? I tried typing it in my Flash project like the book says but it won't compile! ARGH!!!!

Ok... ok backup.... Take a deep breath.

Let's go back and take a look at what we want to do in concept before we start looking at the code again. There are a couple of issues at hand.

First of all, we want to disect the effect, not the code. So we don't want to be typing the examples from the book, especially since they are using actionscript and we should be using actionscript 3.

So (it helps if you READ the introduction to the book) I found that all the source code for the examples are downloadable online. I got it, ran it. Hey, what do you know, it works.

So after studying the example IN the project environment, I learned the following. You can put your actionscript almost anywhere (at least in actionscript 1, you can - just highlight the object/frame etc and open the actions window and start typing). McDonald put some code that was embedded into an Event movieclip, embedding in the Ball movieclip that would receive "enterFrame" events, so that he could update the ball's size etc. Sort of confusing and something to be avoided using ActionScript 3.

It seems that a common practice is to create a layer in the time line and call it "as" for "actionscript". Your code goes in Frame 1 of this layer (highlight frame 1 and click Windows > Actions to type code). When your swf is loaded it will immediately begin playing the movie, so frame 1 is an option to place your initialization code or do things like halt the play head in order to take control over the playhead and the execution.

As expected, within the timeline each frame may contain actionscript. Although this can become messy since your code will be fragmented all over the place. Where are times when it's necessary to put some code in different frames but in general the bulk of definitions and functions should be kept in a separate class definition, .as file then associated with the fla project via document class.

Which brings me to my next lesson, what is the difference between .as, .fla and .swf files.