Tween - (verb) - To generate intermediate frames in an animated sequence so as to give the appearance of smooth movement (also thank you Wikipedia)
So Sherlock, can you guess what kind of tween we're going to be talking about today? If yes, then congratulations, though I wouldn't get too excited, even my cat could figure that out. If no, then I have a query for you: How did you even boot up your computer?
Okay, okay, all mockery and abuse aside, I can admit that definition was a bit cryptic. what a motion tween, or inbetween is, are frames that are generated by moving, scaling, and rotating (or other, those are just the most common) a shape to create an animation. You know that frustrating feeling you have when all you want to do is animate a car driving by, but you have the draw is frame by frame, just to get the dang thing to slide from one place to another? That's what motion tweens are here to fix, just draw your thing, make it a shape, mess around with it, and you got yourself an animation, huzzah!
So I hope this Instructable serves you well in your journey to becoming an esteemed animator. Don't get frustrated and give up, if my words don't make sense to you, I won't go cry if you watch or read other tutorials (actually, do that, it can't hurt). But enough blah, blah, blah, ONWARD TO STEP ONE!!
Step 1: A New Beginning
So just to get going, go ahead and start up Flash and open a new ActionScript3.0 document. Once that's loaded, you'll have a nice blank white stage. If you need someone to go over basic tools and functions with you, you can find all that in one of my previous Instructables here. For now, I'll just go over some quick things. Depending on what you plan to make your animation for, you may want to change the proportions. I just left them standard, but as you'll see later, that left two large black spaces on either side of my video when I uploaded it to Youtube. If you want to make it look nice on Youtube or other video sharing sites like Vimeo, you may want to change your proportions to 1280x720, rather than the standard 550x400.
Also you have the option to change your stage colour. The stage is the background that you draw on top of when you animate. I plan to animate some clouds in the sky, so I'm changing mine to blue. To change the colour, just click on the box labeled Stage, it should be white by default.
Now you're ready to create your masterpiece, so let's move on to Step 2 !