Looking for a recent Cloudflare how-to guide

I’ve been reading various cloudflare topics here but can’t seem to find an up to date / complete “how to” guide.

For example, this topic is over four years old:

Is there a more recent guide somewhere?

My Discourse was set up following the standard docker installation guides and it automatically looks after its own Let’s Encrypt (LE) SSL cert renewals and such.

I was looking for a guide that would help me understand how to stop my Discourse renewing its LE cert and to help me create and install an origin certificate from cloudflare - and anything else that might be required in order to proxy all the traffic through Cloudflare.

Along with any potential gotchas with uploading as we host all our user uploads on a S3 bucket.