Timeline is a special node — NOT a function call. Create by right-click → Add Timeline. Add float/vector/color tracks in the editor. Exec inputs: 'Play', 'PlayFromStart', 'Stop', 'Reverse', 'ReverseFromEnd', 'Set New Time'. Exec outputs: 'Update' (fires every frame while playing) and 'Finished'. Data output per track is named after the track. 'Direction' is ETimelineDirection enum.