First, though, we need to make a new Flash file. First open the Flash program; a new file will open on its own. We need to set the size of our Flash movie, so click on Modify->Document at the top of the screen, to open the window pictured above. We want to set the width and height in pixels (tiny dot-sized units of measurement). You can do that in the first two windows, labeled Dimensions. The first is the width; mine is 320 pixels. The second is the height, which I set at 240 pixels.
Now we just have to set the Background Color; that's the color that will be behind everything else on your movie--like a sky, almost. I'm making mine yellow; just click on the corner of the little white box next to the Background Color label, where the little black triangle is; this will open up your Color Picker. You can click any of the color squares to set it as your background color. Then click OK.
