If you are new to a dungeon, always say it at the start to prevent any "wtf don't you know that mechanic etc" moments.
Since the other 3 should now be aware you are new you can then proceed to carry on without having to fear about messing up.
If no one helps you out/ gives you pointers then that's all on them.
Learning yourself is going to be messy sometimes but hey that's how it goes lol.
Also if you have a tank that's acting all hot and stuff, tell them to back off and chill. Report them after if they fail to do so. As a healer i put hotshot tanks in their places, what do i care if they refuse to tank. We can just vote kick their butt or i can tank till the tank fixes their attitude and rejoins the group.
You probably had a tank who was i90+ with coil gear on, those tanks are usually douchés in the lower ( non 50 ) dungeons.