Thanks to Andrew and Ken for your suggestions. Just today I managed to connect my laptop - nextremote and telescope control through stellarium. The main problem was specifying the correct com port number. It should be a small number - less than 6. I always had 18 or 19. I disable my bluetooth ports and ran the usb serial driver again to get a lower number. They all worked fine and I need to test this outside. If anyone needs any help I can tell you what I did in detail.
I could not have done this without your help because I could not find the instructions written anywhere.
best
Sumith
