Designing an audio system

Hello everybody.

Please take a look at this picture:


I am trying to make an audio system, where the path of the audio file needed is stored in a variable, using other variable as a switch to play it, but, i can’t make it work. After some research, I think the problem is in the action playing the file, it requires some other type of resource pointing to the file, not a string.
Please could someone give me a tip or some advice?


P.S.: Well, as you may have noticed, I am not an English speaker. Thank you for the understanding.