VS1053/SFEMP3Shield Recoding

EDIT: The original content of this post (pertaining to errors setting up and verifying the SFEMP3Shield sketch) was deleted, due to the fact that the issues in question were resolved. Which brings me to my next question.

This program seems to function dependently on the keyboard and computer, specifically the COM7 viewport. How can I edit the code to change this to what I want it to do?
-I want it to play two sounds corresponding to two buttons. When a switch is flipped, or possibly when something is (not) detected as part of a function (magnetic levitation, but I won't get into that here), the buttons will play different sounds. Could I add variables for the buttons, and set up something to 'detect' which way the switch is toggled?

Thanks in advance for any replies. The sketch in question is attached in a Word document (due to character limit).

arduinomp3sketch.docx (29.1 KB)

My guess would be to set up a pin corresponding to the 'Button', and then replace a key code (such as '1' to play a song) with the code for what happens when the button is pressed - however, I have no idea how to do this. I also have no idea how to incorporate the switch, either...