Every pre-expansion class works the same way at the start of HW(combat, gathering, and crafting). Go back to the NPC who gave you the level 50 quest, and theyll have a new quest to offer(if you somehow never got around to doing the level 50, the quest will be offered as soon as you finish the previous one). For some of them it involves introducing you to the person who will hand out the next batch of quests. For other classes who use the same NPC(BLM for one), it just starts telling the story they want to get into over the next few quests. I specify pre-expansion, as the classes added in HW dont need a quest break to introduce the start of their HW lines - youre in Ishgard to get them by default, so you can just continue normally.