These are the main components. The feets are the same, all you need is to print the same 4 times.
Use a heatsource to make the PLA soft so that it will fit easy and properly.  use CA-glue to fix the topbar and the sortbox 1 to the frame. Complement with 2 metal rods. I used brass rods that i slihtly pinced so that i could hold a screw in each end, and i drilled 4 holes on the sides. The rods are needed for stability. One rod on the lower back side and one on the lower front between the sortbox1 and 2.