Type in your website URL and add "/cpanel" to the end
Example: http://www.yourwebsite.com/cpanel
or click on the Cpanel icon in your website manager admin
Your cpanel will open in a new window. some pop-up blockers may prevent the new window from opening until you turn them off or allow pop ups from this location.
If you are looking to update your site and add content/products etc, you would need to access your storeadmin instead of your CPanel. Yours can be found by going to your domain/cpanel. For example: http://www.yourdomain.com/cpanel