CR-10 max is not conecting to raspberry pi

I recently bought a 2nd hand CR10 max. Now i’m trying to connect it wth my paspberry Pi 4B and hav Klipper(mainsail) installed on my RBPI. Now i need to flash my CR-10 max so i can use it with Klipper.

When i follow the steps shown in various youtube tutorials i alwasys get stuck at the point where they flash the printer.

It seems that my printer is not connecting with my RBpI via the USN cable. Tryd multiple USB Cables. Als when i connect it directly to my PC it (Ex. to flash wit cura) it does not show in the devicemanager or COM ports.

Can someone help me with this problem