Help--iPod and Car Issue?

Hey--My family just bought a 2011 Kia Forte EX. You can hook up your iPod in the car. I've looked in the manual for instructions---There's a USB Port--I hooked my iPod cord up to it and it says there's an error. I tried this with 2 different iPods. The car didn't come with a cord--Please--No rude/stupid answers--I'll gladly report--A lot of rude people on here--Just want a good answer!! Thanks!