How to add Cloudflare CDN in WPFC settings

Hi..
My remarks for a simple to use and very effective plugin.
I ve checked it with some of my sites and it works really good.

But I am having some issues with one site that also uses Cloudflare.
I am using WP Fastest Cache on this site, which is hosted on BlueHost but I also use Cloudflare.
Viewing the page source I can see that Cloudflare does not serve WPFC cached version and in GTMetrix much of the benefits from combining JS & CSS are not there …+ some other details.

For example on another site I have WPFC installed (not using Cloudlfare) I noticed that the optimisation is much greater, checked with GTMetrix and scores much higher in many levels.

So I am wondering if there is a way and what is the correct way to fill in the options in WPFC CDN settings in order to improve performance.

Kind thanks again.