How should I adjust warped balcony door frame?
It's hard to see from the photos, but sliding doors are typically leveled (or fit to their stationary counterparts) by turning screw or cam adjusters controlling the height of the two wheels on which they roll. 

Look for plastic plugs covering screw access holes near the bottom of the door, and use an appropriately-sized screwdriver to adjust them. It may be helpful to have someone lift pressure off the door while you do so.