Before you take any steps please back up your files and database. The plugin works only with default CMS pattern. If you manually changed CMS patterns, the plugin might not help you.
Login to your Drupal site.
Choose Modules in your Administration bar on top of the page.
As soon as you have downloaded CDN Module from Drupal.org, choose tInstall New Module and download .zip.
Upload CDN Module from your browser and install it.
If the installation was successful, you will see the following.
As soon as the CDN Module is successfully installed, get back to the modules list and scroll down to CDN. Choose Enable and Save Configuration.
Select Configure in the CDN Module.
Change the CDN module status to Enabled and save the setting by hitting the Save Configuration button.
Choose the Details tab on the right of the screen.
For the Mode choose Origin Pull and enter CNAME specified in the G-CORE control panel.
Ensure that your CNAME record has been configured in a proper way before using it for integration.
Scroll down and choose Far Future expiration, then click Save Configuration.
These steps are needed if you are going to deliver your CDN content via HTTPS. Choose the Other tab on the right of the CDN Module configuration screen.
Enable HTTPS to support SSL.
Integration has been completed! We highly recommend you to check the HTML code of your web page to ensure that URLs have been rewritten properly from your original ones to CNAME from the control panel.
To do that press F12 or open Developers Tools in your browser, choose the Network tab and refresh the page. All static files should have your CNAME in URLs.