Setting up for Sprite Swap

The following steps Follow the steps below to create a Sprite Library Asset, and choose which GameObjects refer to the Asset:

Select the Sprite Library Asset from the Asset creation menu by going to Asset > Create > 2D > Sprite Library Asset
Select the new Sprite Library Asset and open it in the Sprite Library Editor. The editor displays the list of Categories and Labels available in the Asset.
Select + at the lower right of the List to add a new Category. Enter a name into Category (the default name is 'New Category'). Each Category in the same Sprite Library Asset must have a unique name.
Add new Labels into the Category by either selecting + and then selecting a Sprite from the Object Picker window; or by dragging a Sprite, Texture or PSD Importer supported file type onto an empty space within the Categories tab
Create an empty GameObject (menu: Right-click on the Hierarchy window > Create Empty). Select it and then add the Sprite Renderer component.
Add the Sprite Library component to the same GameObject. Assign the Sprite Library Asset created in step 3 to Sprite Library Asset.
Add the Sprite Resolver component to the same GameObject.
Open the Category drop-down menu, and select a Category you created in step 3. The Label drop-down menu will become available and display thumbnails of the Sprites contained in the Category.
Select a Sprite in the Sprite Resolver component to replace the current Sprite rendered by the Sprite Renderer component with the one you have selected.