Where do I get the bus to Jiaozuo from at Zhengzhou Airport?

You can take the direct coach at the Ground Transportation Center of the airport. The English signs at the airport can help you find the direction easily.
By the way, the bus schedules are 9:50, 11:30, 12:30, 13:30, 14:40, 16:10, 16:10, 17:30, 19:00, 20:30 and 22:00. And the ticket fare is CNY 50 per person.