I'mont sure what your question has to do with the article you linked, but you can see which programs are open in two ways:
- In the Dock at the bottom or side of the screen, running applications have a small dot under them;
- You can use the app switcher (hold down the command key and click Tab) to see what's running. (Keeping cmd held down, click tab repeatedly to move from one app to the next - release tab to go to that app, or click Q to quit it).
Matt