So you decide to open the music textbook and search for the key, or a clue to where the key might be.  Unfortunately, there isn't a key to be found in the book, but as you flip through the pages of this Music Appreciation book out falls a note.  Perhaps this note could be a clue to finding the hidden music room key!  
This looks like it is a CLUE! 
​Remember this clue as you continue your search!