Now we move the clip around so that the middle third of the screen displays the desired footage. I was lucky in that the subject didn't move around too much so all I had to do was shift the image slightly to the left so that he remained in the middle third for the entire scene (you might want to bear this in mind when shooting your video). You can use the motion setting to constantly move the image around, but it does get rather overcomplicated and is much more easily achieved whilst shooting! To move the clip around you can do one of two things. The way I tend to do it is make sure that the progress bar is on the extreme left (i.e at the begining!) and then set the points as described in the following image (in this example, I have shifted the image 10 pixels to the left).
As I say, if the subject continually moves around and goes outside of the "third" in question, you'll need to set a series of movement points. To add more points, simply click on the progress bar and type in new co-ordinates. You may find it easier to do it another way - you can physically move the thumb nail in the top right hand window to where you want. Click OK once finished.