Here you can see I am securing the wall panels to the back of the stone pylons I created with screws. The entire structure is standing on its own.
Here is a shot of me securing the panels to the pylons. One detail I forgot to point out before, is the slot at the top of the stone column in the picture. This slot is where the ceiling beam will rest. I will also use screws to secure the beams into the slots. This will make the dungeon structure more rigid.
Here is a shot of the remaining wall panels and stone columns waiting to be put into place.