I'm thinking of buying these wall panels to use as kitchen backsplash and generally to improve the appearance of the strip of wall above kitchen worktops. In the brochure Ikea talk about using "rails" with these panels. On the other hand, they say that the panels are easily applied with a particular type of adhesive. Maybe I'm just thick(!) but I can't under precisely what the rails are for or how they are used. Has anybody bought and applied these panels? If so, how did you do it and are the rails compulsory. What exactly is their purpose? Thank you.