At the back of my boat, there is an entrance to the rear cabin. It's not very tall so a normal door wouldn't do the job.
Instead, there is a door and above this, a sliding hatch. The go inside you slide the hatch forward and then open the doors and walk down the stairs. I assume once under cover, the hatch has a handle inside so you can slide it back again.
In model from, this is all created from plastic sheet. The key is to understand how this stuff works so the runners are long enough for the hatch to move all the way. Either that, or look at the plan properly, but since I'm adapting a plan to fit an existing hull, that's not so easy.
Besides, I like knowing how things work. I'm curious like that.