Positioning, Resizing and Cropping an element in the scene

To move an element within the frame, simply select it and drag.
When you select it, a frame will appear that allows you to resize it.
To crop an element, such as the sides of a video camera, in order to get a vertical look instead of a horizontal one, follow these steps: hold down the ALT key and click with the left mouse button on one of the sides of the element, then, by moving the mouse inside the element, you can crop that border. It is important to note that the ALT key must be held down during the whole process. This process can be repeated on all four sides of the element.