I used to be a no-kwtd guardian like you with no friends and no clan. The best advice i would give is watch every raid for dummies video you can on whichever raids you want to do, and then join every post that says “kwtd” and say “I know what to do but havent played in a while, so we might wipe a few times while i remember the strats.” If you are able to adapt and remember the mechanics quickly, (and remember the guide) you should have no problem doing lfg raids. I got my first lfg leviathan like that. I had no idea what was happening in throne room but i pushed on and followed the rest of the team as best i could. Good luck to you and happy lfg-ing!