If your Clevershare 3 USB is not pairing using the USB C slots on the mainboard of your Impact screen, please use the USB C to A adaptor which are provided with the Clevershare 3 USBs.
This can be paired with your mainboard, on any of the USBs on the mainboard (where the HDMI ports are on the right hand side of the screen).
If you have any further issues with your Clevershare 3, please log a support call here.