In TRPG, there's many doors and chests which are closed by differents locks level. Some are very simple to unlock but some other are very difficult and it could be a real challenge to see what it try to hide from you.
To open a lock:
First, you need to watch the combination on the rigth side of the game board. It shows you where each gem must be placed.
Then it's up to you, you must successfully align the gems in their location in order to succeed the lockpicking.