They are attached in the .scn file.
Just load one of the example and that will give you a general idea. I've been doing the hit-and-miss method as far as placement (enter coords and check in Orbiter). Wish there was a tool where you could call up the meshes and place them with a graphical interface, saving the locations to a text file to cut/paste into your .scn...Searched the threads and havent found anything like that yet...so if anyone knows of an addon, or stand alone that could do that, the info would be appreciated.
Mik