Not able to add comments on Gerrit. It rather gets added as Draft. What am I doing wrong?

Comments are published when you make them part of a review. Post a review and the comments will be published with it. (You can score the commit as +0 if you don't have any opinion either way.)

Click on the Reply button in the header. Then Post it.

And since I am not able to add a comment :

When you want to add comments to a specific revision(Patch Set), switch to that revision and then click on reply. This "Patch Sets" option is found on the upper right corner next to "Download".

Had to learn the Hard Way today. :-/