Importing Documents with attached files

Hi all, I am trying to import documents with its attached files but not able to import it successfully. what things need to do while exporting documents and its files or which Items or ItemTypes are required to export. I did the following things:

1. Add all document objects to package.
2. Add all files object to package.
3. Add Document File Relationships object.
4. Add Located objects.

so, Is anything more required to export? Regards, Maddy.