How do you open doors in Star Wars Jedi knight Jedi academy

Some doors open simply by you walking up to them. Some doors can be opened by pressing the "use" button (default is "e"). Some doors require you to find a key to open them, and some are decoration and cannot be opened at all. If you hit a roadblock in the game, I would suggest finding a walkthrough of the particular part of the campaign that is giving you trouble.