Log in to your Drupal site and from Admin bar at the top, select Modules
After you’ve downloaded the CDN Module from Drupal.org, select “Install new module” and upload the .zip
Upload the CDN Module from your browser and install it. Hopefully, everything will install successfully. That’s something your hosting provider can help you with.
Once the CDN Module has been successfully installed, go back to the Modules list and scroll down to CDN. Select Enable and Save Configuration.
Select Configure from the CDN module. Change the status of the CDN Module to Enabledand Save configuration
On the right hand side of the configuration screen, select the Details menu tab. In Mode, select Origin Pull and enter the CNAME record generated when you created a CDN Resource. See How To Set Up A CDN Resource.
Scroll down and enable Far Future expiration. Save configuration.
STEP 8 (optional)
On the right hand side of the CDN Module screen, select the Othertab. Enable HTTPS for SSL support (optional). See how to Set Up SSL.
Your done. Test the configuration and run a Pingdom speed test.