Then we determine the required length of the racks, for this you need to choose the height of the ceiling, as well as the thickness of the floor and ceiling. I got 2500mm ceiling height, 200 mm height floor lag, 50 mm floor thickness, 50 mm ceiling thickness. Total strut length 2800 mm. We saw the right number of racks and fix them one at a time: 1 nail to the lower strapping diagonally, 3 nails to the floor of the floor through. We start with the corners, there we immediately put two racks with a corner: it is more convenient to fix them to each other. Metal corners were additionally used in the corners to fix the racks.