I've done the following:
- Created an account with aws.amazon.com (Amazon Web Services) to use their cloudfront service. You can choose any of the other w3tc supported ones if you prefer.
- On the w3tc General Settings page enable CDN and choose Amazon Origin Pull (have not used Push - with pull everything is automatically pull to the CDN as needed).
- On the w3tc settings page I have created 10 CNAMES (cdn0.xxx.com to cdn9.xxx.com) to use my own hostname and spread across multiple hosts for parallel download... 10 might be a bit much... you could probably get away with 5...
-- You need to:
--- create the cnames in your DNS editor on your hosting account
--- add the cnames to the Cloudfront distribution
--- enter the cnames in w3tc
And that's pretty much it...
For a bit more detail on creating cnames and etc. see these resources:
Sorry this is a bit brief... If you have any questions please ask and I will try to answer them...