Hello Adrian,
Could you provide a screen shot of what your screen is showing? I'm uncertain by what you mean by Document Library is empty. Document grids, like the one in the Customer screen, shows any linked Documents. If there are no iinked documents, then you can click 'Documnet..' and choose 'Link an existing document...'. You select a document through here and associate it with a record. If the document is not there, you can update the document and attach it to the record. Once the documents are in the grid, you can search by Folder name.
- Greg