Now you will begin the process of modifying the DNS settings for your custom domain so that e-mail goes to your Outlook.com Premium account.
This process will be very similar to the verification step you completed earlier except you will be entering the required MX, CNAME, and TXT records to route your e-mail to Microsoft and your Outlook.com account.
You will also be asked to remove any old MX records for your custom domain in this process.
Again, if you run into any issues get your registrar in a support chat and let them help out.