Does your radio have Pandora built in? If yes, can you tell me the make and model please?
If not, then you will want to do the following :
1 Download the Pandora app from the app store on your phone
2 sign into Pandora or create a new account if you don't have a Pandora account
3 play the music on your phone with the app
To use it with a car that has a bluetooth stereo and not built in Pandora, simply follow the instructions above and then pair your phone to your car and you should hear the music over your car speakers.
If you want more detailed directions, please tell me which step in steps you are having issues with. I see you requested a call, but the payment didn't go through. No need to pay more for a call though, I can help you here.
If that solved your issue, I would greatly appreciate it if you could please rate my answer. If you need more help, just let me know.