The car rental counter is located to the right of the airport exit (after customs, still inside the arrival hall). Many rental company counters are clustered together, making it easy to find. After completing the formalities at the counter, you can walk down to the parking lot to pick up your car. There are signs indicating the pick-up location, so it's not difficult. The pick-up and return locations are in the same area, so you can send yourself a location when picking up the car for easier navigation back. Note that the parking lot is on the ground floor. Simple navigation might lead you to the second floor (arrival level). So, after navigating to the airport, make sure you're following the signs for car parking. Otherwise, you'll be going up and down floors, which can be a little inconvenient.
Everything else is fine; just follow the instructions on Ctrip. They accept dual-currency credit cards (with the UnionPay logo) and magnetic stripe cards. They accept translated driver's licenses.
The vehicle doesn't have a reversing radar.
I booked a child seat, but they didn't provide one. Luckily, no police stopped me, so it wasn't a problem.