@koumudini.bhute I could not find your Gerrit account earlier, but I’ve found it now and added it to the IBM CLA group. You should see it listed under http://review.couchbase.org/#/settings/agreements ; please ensure it is there (the screenshot above is from a slightly different page).
Once that’s there, the CONTRIBUTING.md URL posted by Dave Rigby should tell you what you need to know about proposing a change to Gerrit. You’ll need to add an ssh public key at http://review.couchbase.org/#/settings/ssh-keys and then ensure that your SSH configuration is such that it will use your key. You can verify your SSH configuration by running
ssh -p 29418 email@example.com
You should see something like
**** Welcome to Gerrit Code Review ****
Hi Chris Hillery, you have successfully connected over SSH.