How to Make a Window Bigger or Smaller on a Mac

What you need: A Mac. These steps use a Finder window as the example window.

1. Click Finder (the blue smiling face) in the Dock, the row of app icons along the edge of the screen.
2. In the menu bar at the top of the screen, click Go, then Documents. A Finder window opens.
3. Look at the upper-left corner of the window. Three round buttons sit side by side: red, yellow and green. Do not click the red one, because it closes the window.
4. Click the green button. A menu may appear when the pointer rests on the button; click the green button itself. The window grows to fill the whole screen, and the menu bar and the Dock disappear.
5. To make the window smaller again, move the pointer to the very top edge of the screen and keep it there until the menu bar slides down and the three round buttons appear in the window's upper-left corner.
6. Click the green button.

Expected result: The window returned to its smaller size, and the menu bar and the Dock are back in view.