Since you have provided no real details in your post, I will make some assumptions. I will assume that the Pandora app is running on your Apple iPhone. If my assumptions are correct, you should be able to connect the iPhone directly to the vehicle using the iPod/iPhone cable connection located in the glove box. You will then need to select the "Portable Audio" tab from the "Audio/Video" menu on the touchscreen headunit. Then you will select the "iPod" option. At this point, whatever audio you are playing from the phone will begin playing through the cars sound system.
*IF* you want to stream the Pandora audio from your phone without physically connecting your phone to the vehicle, you will need a Bluetooth adapter such as the Bovee (available on Amazon).