Since the latest version of Raspian OS ( Debian Stretch ) the configuration of a static IP address changed a little. If you enter it the old way into the /etc/network/interfaces you might end up in a "No wireless interfaces found" error.
Most WiFi networks send their names or SSID so you could easily find them on your device. You could also
To play mp3 files on raspberry pi you could use the omxplayer. Install it over terminal via: sudo apt-get install