To do this you take the same principles that you would in photo motion. Put the video clip into your Timeline and then select it so it goes into the Viewer. From here you can then go into the motion tab to change the way the image appears. In the Timeline, available in the motion tab, set a marker at the beginning of the clip or wherever you would like the zoom to begin. You then set a marking point at the end of the clip or where you would like the zoom to end. Here you are going to change the size of the image on the second marker only. You will do this in the left hand size numerically, which is the most precise way to do it. Go to the second marker and place a higher numerical value for this place, comparatively based on what the starting size was. Remember, the larger change in image size the faster the zoom will look. It is always best to make the zoom as slow as possible, that way it retains its dramatic appeal but does not become distracting or overly manipulative.