ok, so I've just figured that out, and maybe this will help someone in the future.
so basically, you need to get a quest, something about "go to the war table to get specializations". this doesn't appear at your first visit to the skyhold, I guess you need to travel somewhere and get back (after you gain lvl 10, but I'm not sure), maybe even twice.
if you have the quest, then go to the war table, activate the ferelden side, and somewhere on the left/middle side of the table will be this thing you need to use, like any other, um, 'quests' on the table. you know, the little black thingies, don't know how to call them. anyway, this one is called "specializations for the Inquisitior" or something very similar - you'll know when you see it.
so, my problem was, I wasn't sure what I was looking for, I thought the trainers should just magically appear, aaaand I was wrong.
and sorry for my poor english. I hope you'll understand something. cheers!
Thanks! You just helped me out big time.
