Hi Pete,
The virtual COM ports are installed when you:
1) Install the Microbit Setup Manager (installs the drivers)
2) Then plug a USB cable between the RRC and your PC
You can then use the port by:
1) Check the ports assigned by Windows in your Hardware Manager under the ports
2) Change the port (e.g. COM2) to USB you want to use under the serial settings (use USB to "yes")
3) Tell your software to use that port (Windows port number, not RRC)
The software you use needs to match the way you key your RRC. I use TRX-Manager, and just tell the program to use PTT via CAT. Alternatively, you can use RTS or DTR over USB (change under I/O settings).
73,
Mitch DJ0QN / K7DX