Just print all three parts, push the cables through the big hole and then squeeze the two halves of the plug into the opening.
The author remixed this model.
SJB4127 made great parts to get an IKEA Metod cabinet airtight (or at least somewhat more airtight), but his solution for cables didn't work for me, so i modified his middle insert with an opening that allows the power cable, the AMS connector and the PTFE tube to pass through, because in my setup power comes from outside the cabinet and the AMS sits on top since it does not need to be within the airtight component. You will still need the left and right parts from his original model.