The best solution would be finding someone who could make an addon.
If you want to do this with JS, you can try adding their script to the project, set its purpose to "Import for events". Then call its functions from the event sheet, for example showBanner()
You may need to call onDeviceReady() function directly to initialize the API, I don't know if the event listener will work in C3 game.
This will be difficult to test, because you'll have to build the app every time with this cordova plugin, it won't work in preview. If you are testing on Android, I suggest collecting logcat logs to check for console and error messages.