It is possible that you can search for this subject very much and cannot find detailed info. Here is the ways you can do this;

1. Use way : my computer > properties > hardware
2. Click “Add new hardware”.
3. Select “I have already connected the hardware.”
4. Click “Add a new hardware device”.
5. Click “Install hardware I manually select.”
6. Select “Ports (COM and LPT)”
7. Click “Next”
8. Click “Communications Port”
9. This way you are adding an additional COM port.