DataOne has a good description of file name best practices.
Source: File Naming: a four-part video series from North Carolina Department of Cultural resources under a CC-BY license.
Metadata - is data about data. It's structured information that describes content and makes it easier to find or use. A metadata record can be embedded in data or stored separately. Any data file in any format can have metadata fields.
At a minimum, create a readme.txt file that contains the basic information about the data, contact information, language, dates, file formats, etc.
More on metadata UCF Libraries Metadata guide