The OBD-II port on a 2007 Chevrolet Aveo is typically located
under the dashboard, on the driver's side. It's usually near the steering column, but it might be slightly tucked away. You'll be looking for a 16-pin rectangular connector.
Because of the variations in dashboard design, it's often easier to find it by feel than by sight. Reach under the dashboard on the driver's side, feeling for a connector that matches the description. A small flashlight can be helpful.