Park, then go to reception, and they will tell you what number lane to join.
You stay in the car, drive it in, and will be asked to move the steering wheel, turn on lights etc. But usually they will help you, if you do not understand.
You go on a rolling road, car is tested for emissions, all the usual things.
If the car fails, you have so many days to get it fixed and to take it back. Reception will then send you to a special lane, for re tests.