You can preview your animations in your banners by clicking the Play icon button, and pause the timeline at any point by clicking the Pause icon button. You can also restart the animation playback from the beginning by clicking the Restart icon button.

To jump to a certain part of the timeline, you can click on any point in the timeline Seconds header on any banner, or you can click and drag your mouse left and right to scrub through the timeline that way, too.