>>389467470
I've only tried the first one at level 23+ but I forgot to pick up the quest for it before going in. It is the most basic type of MMO dungeon, similar to the naga cave/lab with rooms of mobs and a boss at the end. The quests add some simple busywork. We actually got fucked up by the boss but we were underlevelled and I couldn't figure out what the game was telling me to do to avoid the one-hit AoE (It wants you to jump but the arrow looks like it's telling you to do a backflip or something).
Second dungeon is level 32, 40 for third. After all 3 quests you can climb the giant thing in the sky to access raids. There's also a buggy world boss in the final levelling area.