The File Name box is where you specify the names under which your imported media files or project files will be stored.
Each type of input source has a default filename assigned by Studio. For instance, the default filename when importing a Snapshot is "Snapshot". To change it, click in the space and type the name you want.
The Importer never overwrites an existing file when importing. If a file with the same name as the target name already exists, a sequence number is added to the name of the incoming file.
When importing from file-based assets, additional file naming features are available. By default the naming formula for a file-based input is given symbolically as "[original].[ext]", meaning that the original filename and extension are used.