Newbie Help: Adding Midi to a Muscore Score

I have written an arrangement to a hymn in Musescore. Instead of inputing the hymn parts by hand I'd like to add the hymn parts from a midi file I have to my already created score to edit and finalize. I can't see how to do this, can you help?

BTW- I really love this program. Huge props to those who put this together!! I tell all my friends about it. :)