1) How to create filters?
You can create as many filters as you want. In order to do that go in Structure > Taxonomy > Documents properties.
You have to create the document type AND document properties.
- Document type is the format your document are categorized (PDF, JPG etc...)
- Document properties are another way to categorize your document. It can be used as a filter for your document listing page.
You can see examples of document on the Corporate website

