After inserting a Camera and tentatively positioning and aiming it, select the new Camera Object and open its Properties. Enable "Visible" and "Attached." You'll be returned to a new Window that shows what the camera is looking at, but this view won't be useful until you go to View>Camera>Properties and enable Perspective.
Do not "Examine" or otherwise fiddle with the viewpoint in this window, 'cuz that's almost certain to foul up the camera. Open the Window menu and note that it now contains a "...Camera1" entry. That's your current view, as seen by the camera. Go to your original Window to switch views or modify the camera's location and/or target (select the Camera object with the Edit tool).