Can anyone confirm this or have some say so in this?
From the little that I have found, one way is to do a frame using eggcrate. Connect the eggcrate using some epoxy (not sure what kind would be safe) in what ever shape yo want. Use a spray adhesive to attach either sand or rubbled rock. This way, if any i left out, it wont have a whitish appearance and may grow coralline on it. This frame is then covered by smaller rocks that you want in your tank. This way you can add coral to the unattahed rocks. One hint that I found was to build in some way for your frame to "hold" the loose rocks. One guy had small pieces of what looked to be broken pvc covered in rock rubble sticking out of the frame to hold the loose rock.
I have also found articles of people who have just glued rocks to each other to form what ever aquascape that they wanted, but this does not seem to be smart with a reef tank, unless you builld in some way to add and remove coral when you want or make it in several pieces.