Same thing with adobe pdf reader.
Come on folks, this is basic stuff, why doesn't it work?
I transferred 1.5Gbyte of pdf files to my iPad. They occupy the memory, but don't show up in Acrobat.
I am not sure how you did it. But the steps described in the following FAQ document should work.
Please make sure that your file/folder names do not start with a period ('.'). If they do, they will be hidden on iOS.
Your files/folders on your iPad/iPhone should appear in the Local section. Please see the "Selecting a file location" section of the following document.