Addendum: If you also connect the monitor and computer with the upstream cable (flat plug), the USB ports on the monitor also work and you can connect a camera directly there.

The clip at the back is there so that the cables run along the stand, but it is not a cable channel in the actual sense. Apart from the power cable, three different adapter cables are included, 1 HDMI cable, 1 DisplayPort cable and a cable with flat, approx. 1cm wide plugs. Since my graphics card doesn't have a display port, I connected the monitor with the HDMI cable. However, the USB connections at the back of the monitor do not work and I had to connect the webcam directly to a USB of the computer.

Yes, there is a clip at the back where you attach the cables.