2. Erect the upright post of the shelf, fix the beam and put the safety pin in, so that the beam will not fall. . Pay attention to the height of each floor.
3. If there is a main sub-frame, then the sub-frame and the main frame use a column, and the beam of the sub-frame is buckled on the column used by * * *.
4. After the shelf beam is installed, put it into the shelf laminate, which should be prevented from going from low to high.