To change your DNS settings for your domain.com registered domain, log in to your domain.com account and Click On the "Domain Central" menu link from the your account page.
Click on the "DNS" link
How to configure your sub domain
In the Modify menu, select CNAME Alias
Create or edit the CNAME record for www and point it to yourstore.highwire.com
How to configure your root domain
Enter the IP the following IP address for your root domain: 188.8.131.52
Once completed, click the "Update" button to make save your changes.
How to add a custom domain to Highwire
To add your custom domain, log in to your dashboard and go to Settings>Domain Hosting. If you have an existing domain, click the button ‘Add Existing Domain’. If you have not registered a custom domain but would like to register one, this can be done by clicking the button ‘Register New Domain’.