How do I access the Domain Control Panel?

To access the Domain Control Panel:

1. Sign in to your Business Control Panel. (If you have not yet signed in with your Yahoo! ID and password, you'll be prompted to do so here.)
2. Once signed in, you will see modules for each of your domain names on the "Manage My Services" page. Select the "Domain Control Panel" link that corresponds to the domain whose record you wish to edit.

Source : Yahoo Domains