Golden doors to quest locations

[Smemes]

I've been trying to progress in my first area by doing what I'm supposed to but when I go to the quest areas that I'm given by NPCs, I try to go into the buildings but they have a golden door to them that I can't open. I've been trying to ask around in towns to see how I can open them but I can't find an answer. Any help?

[Trestero]

You need a Divine Harp to open those doors. You find it at a quest location like the other key items, unfortunately there's not much else that can be said to help unless you can get an NPC to mention it and mark it on the map.