Grab a mic and queue up in guided games.
Matching up with people is a gamble. Can take anywhere from 10 to 40 minutes in my experience. It’s awesome when you find a group ready to teach, but honestly I just leave queue most of the time and do something else if it takes too long and I want to play.
I wouldn’t recommend just sitting around waiting for a group. I usually straighten up the house or start playing guitar while waiting for a group. Good luck.
LFG is a lot faster, but the quality of your team is gonna be potentially less helpful.
Good luck. Finding a sherpa is very hard because you have to endlessly refresh lfg for a long time. I advise finding a new clan that raids regularly, this is what i did.
Have you checked the 'Find Fireteam' section yet? Endgame content like raids frequently have people looking for teams to run; look for those that have players teaching others or create a post of your own stating that you're interested in learning.