The ladder just hooked onto the door, nothing complicated. I don’t ever recall flying without it on board. I do know that rather than bother stowing it once the door was closed, some crews merely unhooked it and left it on the door. It was a bigger gotcha if the rear crew didn’t move the flight deck ladder back to the central position and you didn’t check before descending. It was a long way to the ground as a few pilots found out.
YS