To create a new Animation Clip, select a GameObject in your Scene, and open the Animation Window (top menu:) Window > Animation > Animation.
If the GameObject does not yet have any Animation Clips assigned, the “Create” button appears in the centre of the Animation Window timeline area (see Fig 1: Create a new Animation Clip).
Click the Create button. Unity prompts you to save your new empty Animation Clip in your Assets folder.
When you save this new empty Animation Clip, Unity does the following:
All the required elements of the animation system are now set up, and you can begin animating the GameObject.
If the GameObject already has one or more Animation Clips assigned, the “Create” button is not visible. Instead, one of the existing clips is visible in the Animation window. To switch between Animation Clips, use the menu in the top-left of the Animation window, under the playback controls (see Fig 2: Adding more Animation Clips).
To create a new Animation Clip on a GameObject that has existing animations, select Create New Clip from this menu. Again, Unity prompts you to save your new empty Animation Clip before you can work on it.
The above steps automatically set up the relevant components and references. However, it is useful to understand how the pieces connect.
The diagram below shows how Unity assigns these pieces, starting from the new Animation Clip in the Animation Window (see Fig 3: Animation Clip Diagram).
After you create a new Animation Clip, you can now see: