How to make a random structure?

i am not sure at all if it actually is the problem, but i think that you need first to make for each of them (except the rotated ones) structures, like any structure, it would generate naturally BUT, you don't make them generate, so they are present inside of the workspace just like the entrance, but the entrance generated naturally, unlike its parts that you added in the workspace, i hope i explained this good enough, i really hope this helps