A second-by-second timeline consisting of a numbered sequence of thumbnails is displayed at the bottom of the editor. Each thumbnail contains a snapshot of the content to be displayed in that second. Navigate to a specific point on the timeline by clicking on the appropriate thumbnail.
Understanding the role of the timeline is crucial to managing when and how long content is displayed. When adding content, the points on the timeline where the content is to enter and exit are specified. The content will be displayed for each second between the enter and exit points. For more information on this topic, see Adding to the timeline. The length of the timeline is determined by the greater of the backdrop duration and the overlay content length.
Check out the video below for help with the timeline.