Follow the below steps to create the bones and skeleton for animating your character:
Select theCreate Bone tool to begin creating the bones of the character skeleton.
With the tool selected, click in the __Sprite Editor __window to define the start-point of the bone. Move the cursor to where the bone should end, and click again to set the bone’s end-point.
To create a continuous chain of bones, select the Create Bone tool and click the end-point of an existing bone. The new bone is started from the end-point, creating a chain.
Once all bones are created, generate the Mesh geometry for the Sprites. It is recommended to use the Auto Geometry tool to autogenerate the Sprites’s geometry Mesh. Then refine the geometry with the Create Vertex and Create Edge tools.
To edit the bones that influence a Sprite, select the Bone Influence tool and double-click a Sprite to select it. A list of bones currently influencing the Sprite appears.
To remove any of the listed bones, select it in the list and click '-' to remove them.
To add a bone, select it in the Sprite Window and click + to add it to the list.
The weight attached to vertices affects the influence between bones and the Sprites' geometry. Select the Auto Weights tool to autogenerate the weight of a selected Sprites. To generate weights for all Sprites at once, deselect all Sprites before selecting the tool. Refine the weights of the vertices with the Weight Brush and Weight Slider tools.
Test the skeleton rig previewing poses with the Preview Pose tool. Move and rotate the different bones to check their influence on the geometry Mesh. Previewing poses can also be done while using the following tools: the Weight Brush, Weight Slider, Bone Influence, Auto Weights, and Visibility tools.
To restore a skeleton rig to its original pose, select Reset Pose. The default pose can be edited with the Edit Joints tool.
To begin animating, drag the Asset into the Scene. This creates a GameObject that reassembles the imported character as it originally appeared in the PSB file in the form of a Prefab. The Prefab contains multiple child GameObjects in the order that represents their layer hierarchy.
With the new GameObject in the Scene, you can begin animating it with the general Unity animation workflow and tools.