Used a 5/16 concrete bit and some plastic coat hangers to cut into dowels. Then my brother and I dry fitted pieces together to visulize where we wanted shelves etc... for larger pieces I would drill 2 holes underneath and put pegs in for support.. once we had all our pegs in and ready..we scuplted epoxy "instant ocean, fluval brand" in the joints and around the support pegs.. after that we waited about an hour and the rock wad hardend enough to place back into the tank.