This is our example database coming with the plugin. It shows you how to pick a PDF file on disk or import a PDF into a container. Then it can initialize the control and show it on the layout. How the PDF looks is defined by the preview handler coming with Windows (10 or newer). Same on macOS, where the preview control has a minimum user interface, usually just a scrollbar.
Since on macOS, we use the QuickLook preview, we can also show other file types, e.g. files from Word or Excel.
Please try and let us know whether you like it.