Using a third party plugin in ionic


I’m developing a cross-platform app, but I want to integrate Box ( in it. I need to have the preview SDK in my app.
The problem is they only have non open source SDK’s for the native platforms iOS and Android. My question is how do I integrate these? I understand somewhat how to import them, but I can’t seem to figure out what to put in my interface class since I can’t see the source code of the SDK.
All help is really appreciated