Custom dungeons

I saw a server that has a custom made dungeon that supposedly resides outside of the green ghost wall.

I’ve searched and searched and can’t find any information on how to do this kind of thing, how to build outside of the wall or how to pull in base game architecture (stone walls, parts from black keep, etc…) Anyone have some clues they can toss my way?

Thank you, great information here. So you can teleport to a point and then create a warp or portal to it.

How do you do the map part? Know of any practical instructions or tutorials on how to do this?