So on Godaddy, I had a DOMAIN A linked to a webhosting A provided both by Godaddy.
I transferred that DOMAIN A to CloudFlare registrar and that worked fine being pointed to Webhosting A.
Now I want to point that same DOMAIN A to a Webhosting B which is hosted on Dreamhost, but I have no clue how to do that?
I simply tried to copy the DNS A record from the Dreamhost to my DOMAIN A but that doesn’t seem to be working, it is showing that the page does not exist.
Ok, if it’s the same domain name, you just need to update your DNS records here to match the ones at DreamHost, which it sounds like you’ve done.
Sometimes a major change necessitates bypassing Cloudflare while working out the kinks. Try the “Pause Cloudflare on Site” option from the lower right corner of the Overview page here while you troubleshoot. When the site is up and running with HTTPS, go ahead and un-pause Cloudflare.