You can download the PIA app right from the Apple app store here:
Once it downloads and installs, simply launch the application and input the credentials we sent you when you signed up (it may ask you for a PIN, which is just your pin code you use to unlock the iOS device). Then you can choose a server by tapping on the current region right on the main screen below the OFF/ON button. After you choose the server location you want, you can slide the button to ON to connect to that server. If you wish to change servers at any time, you can slide the button to OFF, then choose a new server by tapping server selection and choosing one from the list. Slide the button to ON again and you will be connected to that server.