Generally, the graphical design of the icon suggests the function, concept, or feature it represents. These are icons that you are likely to encounter on a regular basis as you get to know the operating system. Depicted below are some of the more common icons. Move the cursor over an icon and a description will appear in the status bar at the bottom of the browser window. If you are using a PC right now you will also see a description next to the icon itself after about 1.5 seconds.
All software programs have their own custom icons.
As you use the computer you'll get to know what the various custom icons represent. Here are some custom icons that you can check out. In general, you left-click once on an icon to highlight it. The purpose of the highlighting is to provide feedback that the icon has been selected. To open the file or start the program the icon represents you double-click the icon.