Hi JayKay38,
All the ferries which have operable ramps/doors etc have a control panel for them. There is one on the onscreen controls and it is also in the wheelhouse. My picture shows the "Albatros IV" panel. 1. is the control for the stern ramp, which you push forwards. 2. is the open close button. You can see that 1. is in the position ready to open and 2. has opened the ramp. The control panel is different for all the ferries but the general idea and operation is similar.
Regards,
Angus.