What is the correct procedure when coupling up a multiple-axle trailer?

Your answer is correct. When coupling a multiple-axle trailer, you should reverse the truck up to the parked trailer. This is the safest and most practical method because the truck is easier to maneuver precisely, while trailers, especially those with multiple axles, can be very difficult or even impossible to push by hand. Moving both vehicles at the same time is unsafe and can cause accidents. Always make sure the trailer is secured and the area is clear before reversing the truck. This method ensures proper alignment and minimizes risks during the coupling process.