Job quests?

[Zomkei]

For the secondary class do I just have to go to the certain guild master to obtain that secondary class?

Yes, you are correct. As long as you have unlocked the airship to travel to the three city-states you can unlock any class aside from DRK, AST and MCH. (Need to reach HW for those.)

Edit: If you're going for DRG, then you need to unlock MRD from Limsa Lominsa Upper, (x11, y6) It's easy to see the classes on the maps because of the icons. Good luck!