A JFrame represents a window on the screen. Widgets like buttons and labels can be added to the JFrame. There are four steps to creating a GUI: 1) make a JFrame, 2) make a widget, 3) add the widget to the JFrame, and 4) display the JFrame. To make a button do something when clicked, you need to use event handling by implementing an interface like ActionListener and defining the actionPerformed method. This allows the button to call the actionPerformed method when clicked to trigger an action.