The rail must be inserted only in the correct direction

As for the reviews with a star, I can refute. The rail must be used the other way around, so not as to the product pictures here and on the packaging, but the other way around. That may be a bit misleading. if the track is reversed in it, is not the star shape, the track is right around it, all forms are correct. I was only irritated by the 1 star reviews, had then specially called for Bosch, who explained it to me. For me, the track then went very easily, so I have the metal bracket lightly pressed upwards so that it is pleasantly heavy to move.