The model relies on the 4040 extruded aluminium having dual channels on the sides.

If you print the base in the wrong orientation in the slider, the protruding screw mount will make it not sit flat in the slicer causing issues. You can either print it on its side as it is or like a table. I found when I printed it on its side, I had to file a rough edge from the supports, but then it has a good snug fit when inserting it into the 4040 channels

I used a very small dab of super glue on the top edge to ensure the rear panel doesn't go anywhere, it is still easily removable