How to make boss battle map ala map30?

Hi,guys,i am new to mapmaking,need some info of how Boss battle maps are made.I want to make map with final boss ala map30 of Doom2,but i dont know how to make the walls with textures properly.Can omeone give me tips?

It's difficult to explain, but if you look at it in the map editor, you'll see that it's actually essentially a series of very thin steps, with the bottom textures (9, 5, and 7) placed on the lowest step, the middle textures (8, 4, and 6) placed on the 2nd step, and the upper textures (1, 3, and 2) placed on the top step, with a hole in the middle top step for the "brain" to get put into. Since Doom Builder 2 allows you to save map geometry selections out as prefabs, that would probably be the easiest way to recreate it--to actually save the wall out as a prefab. Select the sectors, then click Prefabs > Create from Selection...--this will allow you to save the wall separately from the rest of the map and open it up later in a new map. Then you just have to drop in the brain (which is what takes the damage), a spawner (which generates the cubes), and at least one monster target (which is the destination the cubes fly to), and you should be good.