Nano vertex k8600 doesn't connect using usb

I am trying to install a fan duct on my nano vertex k8600 3d printer, I designed and printed the part and connected the fan to the led 12v port (just like this guy did I tried modifying the marlin software (to limit the fan speed), I don’t know if I did it right but when I tried connecting my 3d printer to my pc using the usb the problems started. The printer shows up in device manager at the ‘other devices’ as USB2.0-Serial with a exclemation mark and there doesn’t get a driver installed, I already tried letting windows search a driver and I searched for a driver online but I can’t seem to get it work. The printer thereby doesn’t show up in Repetier and when I press ‘connect printer’ the error ‘No port available for autoselect. Please connect your printer first!’.
I can’t find any explenation in the manuals online so I had to ask it here.
Thanks in advance!

Hello @Erny9

You need a USB to serial driver “CH340SER” or “CH341SER”

As for the K8800 in :

Or may be you can use the same USB Serial driver for the K8400 :

The USB to serial driver is also normaly embeded in Arduino IDE install

To “build” and “upload” a recent marlin (v2.0.x) you may need VSCode + PlatformIO + Auto Build Marlin :

Have a nice day !