iPhone to NAD 316

I have an iPhone with a lightening connection and an NAD 316BEE v2. I believe that it is possible to hook them up and play music from the iPhone over the amp. I can either get a lightening-to-RCA cable (my preferred method) or lightening-to-3.5-headphone jack, the female version of which is located on the front of the amp. Which one will work? Which one is best? I guess the phone is outputting a digital signal. Do I need a DAC before it reaches the amp or will something—the cable, the amp—handle that? Many thanks.