From Audacity Manual
The Timeline displays a horizontal ruler above the tracks measuring time from zero (the start of the track). Depending on zooming the ruler may span minutes of audio or give a "close up" view of a few seconds or fractions of a second.
Legend for symbols displayed on the ruler
- The selected region: (when present) is shown as a shaded region on the ruler. Pressing Play or Record on Transport Toolbar plays or records from the left edge of this region.
- The editing cursor: (always present when there is no selected region) is shown as a black vertical line. When "Quick-Play" is not active, the playback start position cursor is attached to it . Pressing Play or Record plays from this cursor position.
- The playback cursor: (when playing or paused during play) is shown as a green triangle.
- To start immediate "Quick-Play" playback from a particular point (even if the track is already playing, recording or paused), hover over the Timeline until the mouse cursor changes to a hand, then left-click without dragging. Playback will continue to the end of the track.
- The record cursor: (when recording or paused during record) is shown as a red triangle.
- Quick-Play region: A selectable region that plays immediately "on demand", shown by arrowheads with a line connecting them.
- To start "Quick-Play" of a region (even if the track is already playing, recording or paused), hover over the Timeline until the mouse cursor changes to a hand, then drag in either direction and release. Playback will continue to the end of the Quick-Play region. Neither an already selected region nor the editing cursor is modified by Quick-Play.
Examples of the Timeline in use
For other methods of navigating to playback points or areas, see Playing and Recording.