Now, there's no use entering code if you don't know what it does! So let's take a look at the code above:
The first line is a conditional clause: this means it checks one thing before it does another. A good analogy is driving: you don't press the accelerator without starting the car, (or maybe you do, but you shouldn't), so you've got to check if the car's started first, before you press the accelerator. This conditional clause asks if our variable startup is equal to nothing ( "" indicates nothing). Why do this? Because we're going to loop back to this frame and I only want to carry out these operations once, not every time we come back. That's where the second line comes in: by setting our variable startup to any value other than nothing, we ensure that these instructions will be ignored every subsequent time we visit this frame.
The loadVariablesNum command is the important aspect here though. This command replaced the standard loadVariables command in Flash 4 and is used for loading variables into Flash from an external source, such as a text file on the server. These variables are loaded as expressions, (numbers), rather than strings. counter.txt is the name of our data-storage file, which we will deal more with later. The remainder of the code, produces a random number, random (999999), and concatenates (attaches) it to the end of our file-name, after a question mark. This question mark, random number combination is effective against browser cache conflicts.

Now on to Frame 2. Double click your keyframe in frame 2 to open the Actions inspector for that frame. Now enter the following code:

What kind of statement is this?
If you said 'It's a conditional statement Jesse!' then give yourself a pat on the back. Yes, conditional statements are everywhere. This one is a bit more complex than the last though. First it checks our condition, in this case loaded == "1" or 'Does the variable loaded hold the string value "1"?'
This is where the extra variable in our text file comes in. Data files won't always load in the split-second between one Flash frame and another. In this case they probably will because the file in question is only a few bytes long, but it's good practice to add an additional variable at the end of your data file which you can use to check if the data file has completed loading. If the data file has completed loading, Flash will go to and play, Frame 3. If, somehow, the file is not yet fully loaded, Flash will go to and play frame 1. This is the loop I mentioned earlier and the reason behind the conditional statement in the first frame. In the highly unlikely situation that the data file is not yet loaded, Flash will loop until it is.