OK Matt, I downloaded the software myself so that I can give you specific infomation. I have the newest version and don't want to confuse with features or procedures that are differerent.
You can install the software by double-clicking on the .exe file you downloaded. The first time you run it, you will have to register it on-line. It is easy and fast. I just entered the information and by the time I got to my email, the unlock code was waiting. Fear not, Serif is a reputable company and I've been using their software for well over ten years now and have been a beta tester for the last six years.
Anyway, once opened and running the steps are simple. Just go to file/open and navigate to the picture you want. If you want the whole picture fine, if not, you can use the crop tool to get rid of what you don't want. Select the crop tool (the funny looking box, third down on the left side toolbar. Drag a box over your picture and reposition and resize it to what you want, then left double-click inside the box.
In either case, go to image/image size. There a dialog box will come up and you can change the picture's physical size. If you have "maitain aspect ratio" checked, you can change one dimension and the other one will follow. I usually change the "width" to 640 pixels, and the hight will go automatically to 480 or smaller. If not, change the hight and the width will follow.
The second step is to go to file/export optimizer. A dialog box will come up with the picture file size above the picture. There is a slider to the left. Move that until the file size is less than 65K. Newer versions of this software allow you to change it in 1% increments, this slider is a bit course, but gets you there nonetheless. Once you're there, press "export" and save the picture by whatever name you want and wherever you want. The export dialog box is typical of most Windows apps.
Here is a picture I took about two years ago with a different camera. The original was almost 600K, and by resizing and optimizing, it is now 52K and doesn't look too much different on screen.
I hope this helps..