Measure the aquarium where you plan to mount the grow bed. Size the grow bed to fit comfortably inside the aquarium.
Cut your plywood sheet to the desired length and width. Cut the beams to match the length and width of the plywood board.
Mark and drill two holes in the beams, then screw the pieces together at a 90-degree angle. Cut two more beams and lay them across the grow bed.
Measure and cut the legs for the hydroponic frame. Set the frame where you want it then measure the length of the legs you will need. If the spot you have chosen has a slope, the legs will need to be different lengths to accommodate the sloping ground.
Pre-drill the holes and set the legs to the side of the grow bed frame. Make the legs flush with the edge of the frame then screw the them into place. Attach the frame to the plywood backing to complete the aquaponics frame.