To open a pdf file on iOS device you should use the InAppBrowser plugin as in our sample app
. On Android, the app attempts to open the PDF file in the default browser and the browser launches the default PDF reader app so you need such reader installed.
For your convenience I slightly modified this sample
in order to download pdf file and open it.
However this could be an option when you attempt to open pdfs and images.
If you want to open different type of files you can try with the plugin you have found and to do that you will have to import it as described here
I don't know how reliable it is but notice that it is designed for Android platform only.