From docs:
-f, --files: Location of *.rdf(.gz) or *.json(.gz) file(s) to load. It can load multiple files in a given path. If the path is a directory, then all files ending in .rdf, .rdf.gz, .json, and .json.gz will be loaded.
Self-managed cluster - Deploy
That is, you only need to provide the path for the files that Dgraph will automatically load all compatible datasets there.