Originally Posted by bearstardiode
... But you say navigate to where the file is. How do I do that?...
You can navigate through your files within the Reader Library. Once you have opened your epub look at upper right corner of the application: you will see two icons (see attached image)
Clicking on them shows you the content of the folder where your file is located (you will get a list or a thumbnail view depending on which of the two icons you have clicked)
On the upper status bar you have the full path, and clicking there you can browse through your folders.
I think this is what you are looking for.