You will find the Minimize, Maximize, and Restore buttons on the horizontal title bar at the top of each window.

To minimize an open window, either select the minimize button or click the PowerPoint icon on the top left portion of the Title Bar.

Maximizing the screen means to expand the window to fill whole screen. To maximize an open window, either select the Maximize button or click the PowerPoint icon on the top left portion of the Title Bar.

Restoring a window means to return a window that has been minimized or maximized back to its previous size. To Restore a window, either select the Restore button on the PowerPoint Title Bar, or click the PowerPoint icon on the top left portion of the Title Bar. Note that if a window has already been Restored that command will be greyed out.