Understanding the use of the Contour Tool

My primary purpose in using Corel Draw is to draw/make scroll saw patterns. Currently I am trying to make a heart shaped box. The instructions I obtained from a video which begins with the Basic Shapes tool, Perfect Shapes icon, select the shape of a heart and draw it on the worksheet. This is followed by making couple of copies of the heart shape for the top and bottom of the box - so far so good - understand what I am supposed to be doing. 

But the next steps are not clear to me and I am having a hard time grasping the meaning. Supposed to create a contour on the inside of the heart shape to match the interior walls of the box using the contour tool. I am lost at this stage. The information I am providing is likely not all that clear as well. But I can't grasp/visualize what this step is supposed to do. 

With this information, don't expect much help. Confusing.