This is a front panel for a 2HP passive eurorack multiple and attenuator.

The potentiometer needs to be thin enough to fit under the panel. I added some photos of the potentiometer I used.

You need to connect all of the tip lugs of the jacks together as well as all of the ground lugs to create a passive multiple. The schematic for a passive attenuator can be found on this page: https://www.doepfer.de/DIY/a100_diy.htm