Log into your GoDaddy account and click “Launch” to show all of your domains.
At this point you will see a “Domains” page, click the domain name that you want to assign to your store. Click the link " Manage DNS ".
In Zone File, you can click on the "Add Record" button to add a CNAME record.
Add the "CNAME" record to map "podcast.mydomain.com" to your podbean site, e.g. username.podbean.com. Set the "host" to "www", and "Points to" to "username.podbean.com".
Don't forget to save the changes after you add the CNAME record.