How to buttonhole?

Lervia KH40001 sewing machine....how do I get the stitch selector to turn from Q onto R, S, T which are in red on the dial. The dial will not turn either way past the yellow Q one way, or the A the opposite direction. I have followed the manual instructions for attaching the buttonhole foot and putting the stitch length and width dials in the correct place, but Jo matter what I do I cannot get the dial to the buttonhole selection of the red R, S or T. Please help