all you have to do is get some PVC
pipe get a drill wil small drill bit some fishing wire
drill a small hole in the rock each rock for the base (use biggest first) then thread all of these rocks going around the PVC
pipe and do this for each layer.
Obviously the idea is have enough LR
so the PVC
cant be seen and in time the PVC
can be pulled out because of all the growth will bind them all together anyways.
and when the PVC
is pulled uot you will have one reall big cave for the fish to flee to.
post pics when you are done, always wanted to do an oct tank for this reason.