The screw on the side requires a Torx #7 key. It also has a slot cut in, but the cut does not extend to the sides of the screw, meaning you need a screwdriver with a blade ideally 3.75mm wide, but no wider.
The cable clamp is a simple metal C-clamp to bend over the cable. A small cable tie may be needed.
The diameter of the rubber tube is 5mm. Removing the rubber tube gives you 8mm.
It does not work with pro snake AX-Highflex 8-core cable (Item 499406) which has a diameter of 9mm. 1mm may not sound like much but I have tried and tried and just does not fit. I purchased 20m and I cannot use it, so it's going straight into the metal recycling.
It is so annoying that Thomann often fails to supply key information on the products it sells. Such a waste.