Importing a MIDI piano file

I'm very new at muescore! I believe that I must obviously be missing something, but can't seem to find what that might be in any of the forums I've seen so far. What's happening is this: I'm importing a MIDI file from Waveform. It's coming from an electric piano. It's just a very basic chord progression, I'm trying to figure this out. When I put it into Musescore, it seems that each note gets its own line. In other words, instead of there just being one grand staff of music, it shows like 16 staffs, one for each note that I played on the piano. See image. Any help to get this to just look like a normal score would be much appreciated.