How to play music from my iPhone to my Hyundai elantra (2012)?

Do I need a chord or something like that?

If your stereo in your car has an AUX port that has a hole that looks similar to the headphone hole on your iPhone, you just need this cord and plug it in to both the iPhone and the AUX port in the stereo, then press the AUX button on your stereo. If your stereo does not have the AUX in port, you can use a product such as iTrip by Griffin. Plug it into the 30-pin charging port of your iPhone and also into the cigarette lighter or 12V power port in your car. The iTrip transmits whatever music is playing on your iPhone over FM radio frequency, so you set a station on the iTrip then tune your cars stereo to that same FM station using the tuner dial or buttons.