Print the right and left sides of the beam in two copies.

The posts have been modified to make it easier to remove the glass.

 The beams have been modified because I found them too massive in the original design. 

To connect the beam parts, you will need an 8 mm diameter tube or pin with a length of 50-60 mm. Additionally, you will need a 3 mm diameter pin with the same length. 

The beam is attached to the base supports with 4 M3 screws. 4 M3  threaded heat inserts with a diameter of 4 mm and a length of 4-5 mm must be melted into the base support.

I assembled the parts without using glue. However, you can use glue for added security.

The connection is quite sturdy. 

There is no additional fixation for the box, except for the edges on the beam.

Large cutouts in the base supports also allow you to place a tray for small items and tools.