SIDECAR not working ! Finally solved.

As a new user of Apple Products, I was definitely excited by the sidecar videos on YouTube and went ahead got an iPad (compatible) to use as a second screen for my Mac. Besides I figured it would be nice to have a portable tablet. I was up for some disappointment as the sidecar did not work. I did everything suggested in the forums and kept looking for every video on youtube but none worked. Finally realized one key feature which actually allows sidecar and was able to repeat the same with other iPad Pro.

If your Mac is not recognizing your iPad to connect (after you have followed all the instructions , same iCloud login, wifi on - you don't need to be connected to any network or internet , bluetooth on)

do this,

connect to the internet on your iPad and open iMessages => Login to your iCloud account , Open FaceTime => login to your iCloud account and Voila! you will now see that Mac shows the Airplay icon and you will be able to connect to the iPad . This has worked with all the iPads i have tried. If I logout of iMessage, sidecar stops working or gives me an error.