To add a custom domain to your site, first find the the site in your sites list, then select "Domains" from the dropdown list.
Custom Domains are available to everyone free of charge!
Next, specify the apex domain that you wish to add. An apex domain is a top level domain like yoursite.com, or myawesomeshades.com. Mavenseed doesn't support custom subdomains like docs.mysite.com. That would be like, inception.
Note: While apex domains will work well, custom sub-domains are currently not supported on Mavenseed.
After you specify the domain to add, and after saving, you should see some instructions for what DNS records to add. If you don't see the instructions, try refreshing the page again.
Here's an example of what you'll see after adding your custom domain.
The last CNAME record will redirect the www version of your site to the non www version.