LG V VX-9800

this is probably something really obvious and it will show how little i know about computers, but when i'm on the "play list" i'm not sure what i need to do to get my mp3's to show up in the "available songs" window.

i guess there should be a way i can direct the program to look in a specific folder, but i just haven't been able to figure out how.

any info would be appreciated.