Associate some more documents

Hello everybody,
I’m trying to learn MarginNote on my iPad and have created my first mind map yesterday with related documents.
A day later I want to add more documents and can’t find a way to associate more pdf-files.
I have imported them yet into the category. In my mindmap I have 11 docs.
And now???
Simply there is no menue-point to associate more docs.
I’m pretty desperate.

What can I do?

O.K. found. :hot_face: