When I import a MIDI file, what happens? Metro loads the MIDI file into the current document as one of the document’s Sections; you can see every section in your document in the Sections window. For more information on Sections, Tracks, and SubSections, see The Sections Window . Hint: To make a stand-alone document out of a MIDI file, begin with a New file before importing. Metro assigns the MIDI file's channels to the currently assigned Original port.