Open cover "2" and cover "3". Through the open roof, press the sliding frame from the side into the guides. On the opposite side, squeeze the spring-loaded slider and pull out the sliding frame in an upward direction.
Replacing the spring-loaded slider: Sliding frame "1" removed. Carefully drill out the head of the rivet "arrow" of the spring-loaded slider "2", knock out the pin and remove the slider from the side.