Flying or skyriding not working after the patch

Hello everybody! I can't use my flying mounts anymore after this patch. I have a lvl 54 hunter. Never played Dragonflight. People say that I should have a button in my general spellbook tab.. nothing there. Other said I should accept the first quest of the Dragonflight expansion. I'm currently 10 quests into the dragon isles and still no flying. Any solutions?