The sequence view in the lower half of the main window can be viewed in either timeline or storyboard mode.

To change between the two modes, select View -> Sequence -> Timeline Mode or Storyboard Mode, or click the Timeline or Storyboard button underneath the sequence tabs.

Timeline Mode

Timeline mode shows all video and audio tracks, and all the clips on them. The width of each clip is proportional to its duration. e.g., A two minute long clip will be twice as wide as a one minute long clip. The duration of a clip can be changed by dragging its left or right edge. A clip can be dragged to change its position, or to move it to another track. Any linked or grouped clips will move too.

For a list of the controls available on each track, see: Concepts: Tracks

Storyboard Mode

Storyboard mode is a simplified view, suitable for quickly assembling and arranging clips when creating a new sequence, or making easy changes to existing sequences that don't make use of many tracks. Only clips on video track 1 (and any audio linked to those clips) are visible. When moving or changing the duration of clips in a sequence that contains clips on many tracks, timeline mode is recommended instead.

The width of each clip is the same, regardless of its duration. Space between clips is shown as a fixed gap, the same width as a clip, regardless of the duration of the space. Clips can be rearranged by dragging them before or after other clips or gaps.