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 wD8j.

dragon age inquisition how to get specialization