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 plugin might not help you.
IPB version 3.2. and newer ones support automatic integration with the CDN
Login to the administration management console.
Go to System settings → General configuration settings
Scroll down to images, CSS and JS URL settings.
Save the settings.
Integration has been completed! We highly recommend you to check the HTML code of your webpage 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.