Returning after a long break: what should I learn first?

If you are coming back after multiple expansions, do not try to learn every system in one sitting. Pick a character, set up keybinds, run follower or normal dungeons, then learn one endgame lane at a time.

Start with UI, talents, rotation basics, and one weekly goal. The rest makes more sense once your hands know where the important buttons are.

For healers, spend time on frames and mouseover behavior early. Bad frames make every fight feel harder than it is.