Here’s how you can add a CNAME in CloudFlare:
Sign in to your Cloudflare account
From the dropdown menu on the top left, select your domain
Select the DNS settings tab
Add a new DNS record with these settings:
Next, set up a page rule for using full SSL for the subdomain you pointed to SPP (unless you’re already using Full/Strict SSL site-wide).
Toggle the orange cloud icon to change the Proxy status to DNS only.