You can move, resize and overlap windows on screen. Following are the basic movements. If you are not familiar with dragging and dropping, see Win Drag and drop
MOVE WINDOW AROUND SCREEN
Point to anywhere in the middle of the title bar (top of window) and drag.
RESIZE ENTIRE WINDOW
Point to a corner. When pointer changes to an angled double arrow, drag to new location.
RESIZE ONE SIDE ONLY
Point to a border. When the pointer changes to a double arrow, drag to new location.
TAKE WINDOW OFF SCREEN AND BRING IT BACK
This is called "minimizing" and "restoring." To take the current application off screen, click the leftmost button at the top right side of the window (underscore/dash symbol).
To restore it back to the screen, click the Taskbar button.
MAKE WINDOW COVER ENTIRE SCREEN (MAXIMIZE)
Click the middle button at the top right side of the window (rectangle symbol). The button icon changes to double rectangles after maximizing.
RETURN TO PREVIOUS WINDOW SIZE (RESTORE)
Click the middle button at the top right side of the window (double rectangles). The button icon changes to a single rectangle after restoring.