How to open Hernand Castle Strongbox

Unlocking the Hernand Castle Strongbox is a fun little puzzle in Crimson Desert in which you have to replicate a melody, but if you're not musically inclined, you might struggle somewhat. To access this safe, you'll first need to enter Hernand Castle and you'll also have to get a key to unlock the door to the room that the box is inside.

Finally, you'll need to acquire a mask in order to actually steal what's inside the box when you're done—the same is true for all other strongboxes as well.