Reading the spells description in your spellbook, tgis basically explains most of them in detail [this spell increases armor, this increases health, this heals you for % of damage dealt so on so on.] After you know what each spell does, head to training dummies to see them working.
Learn the paths in dungeons, even if the dps pulls you can learn the route best to move as generally the tank picks the route.
I would suggest playing bear, or dk for learning the basics in tanking. These are much more accident forgiving then monk and paly, those 2 tanks have the most button bloat as well and would be intimidating for a new tank.
All of this is done in game with 0 actual chat help. I would also add addons such as dbm but if you truly want immesion then its best to know what every mob in a dungeon/raid can do or be prepared to have angry people.