After you have arranged your video clips in the storyboard, you may decide that you want to adjust the length of time some of the clips play. Do this by trimming the video clips in the editing timeline.
First, switch from Storyboard to Timeline view. Then, place your cursor at the beginning or end of the clip that you want to adjust. A red arrow appears, with the instructions click and drag to trim clip. Drag the arrow to trim away the beginning or end of the clip. When you release the mouse, the highlighted portion of the clip remains, and the rest is deleted.
By trimming your clips, you can fine tune your video so that the scenes flow smoothly together.