How to fix Wwise Unity: EventCallbackPackage not found for error??

Question

How do I go about fixing this. I've just integrated this project into Unity, added the AKbank and tried to add a sound to a Unity demo game. I've tried this multiple times and not had any luck the most recent error is the one listed above. I've followed the Wwise courses and followed tutorials and always some error will appear. I have previously posted with no responses, thought i'd try again. I just want to add a simple sound to a game  to try to get the basics down without having to troubleshoot a list of errors.