Run the app from the shelf button under Custom tab or run this python command:
import pk_ghosts
reload(pk_ghosts)

After UI launch, you need to add geometry to the list. 

Make Ghost button will create "ghosts" in current frame.

Update Ghosts button allow you to update all "ghosts" after changing animation.

The functionality of the remaining buttons, can be seen on the picture with the description and also in the video tutorial provided under the screenshots and videos section.

The installer that ran when you downloaded this plug-in from Autodesk App Store has already installed the plug-in.You may need to restart the Autodesk product to activate the plug-in.To uninstall this plug-in, click Control Panel > Programs > Programs and Features (Windows 7/8/8.1/10) or Control Panel > Add or Remove Programs, and uninstall as you would any other application from your system.