The Timeline allows you to scrub through the animation, display timecodes where the keys were created, and display the animation duration in seconds. You can also adjust the settings of the final animation duration and speed.

The Timeline lets you rescale the keyframe data for objects in a scene, which is useful if you want to change the speed in isolated parts of the animation, for example, to create a pause. 

To do so, hold down Shift and select the start and end points of the time interval you want to change. Then, move one of the displayed arrows on the sides of the selected area to the left or the right.

When you change the playback Length, you have two options: fit the animation to the new length or keep the animation length without changes. You can easily change the Speed value if the playback is too fast or too slow.

Note: The playbackSpeed setting is for preview purposes only. If you’d like to apply the speed setting to your scene, press the Bake Speed button..

You can isolate a small animation section by changing the playback range values on either end of the timeline window. You can also crop the timeline to the selected playback range by pressing the Trim button. This will discard the keyframed data before and after the current selection.

Setting	Description
Trim	Trims the animation to the selected frame range.
Loop	Scales the animation to match the preview speed. Use this if you want to permanently speed up or slow down your animation.
Motion Blur Preview	Toggles Motion Blur Preview (Viewport camera must also have the motion blur option enabled).
First Frame	Goes to the first frame.
Previous Keyed Frame	Goes to the previous keyframe.
Previous Frame	Goes to the previous frame.
Play	Plays the animation.
Next Frame	Goes to the next frame.
Next Keyed Frame	Goes to the next keyframe.
Last Frame	Goes to the last frame.
Autokey	Toggles automatic recording of keyframes. Keyframes will be recorded for the current frame when a change is detected for most parameters of your selected object.
Total Frames	Determines the total frame count of the animation.
FPS	Determines the frame rate, or frames per second, of the animation.
Length	Determines the length of the animation in seconds.
Speed	Sets the playback speed for preview purposes. Preview speed is not applied to exported video content.
Apply Speed	Scales the animation to match the preview speed. Use this if you want to speed up or slow down your animation permanently.
Link Zoom	Determines whether to show all frames in the timeline or only the frames within the selection range.
Playback Range	Determines the selection range, which isolates frames for easy editing and playback. Use the left and right handles to set the first and last frames, and drag the central handle to move the range.