[SOLVED] Begiiner problem - layout left-main-right

I try to switch to layout-style left-main-right, but it doesn´t work.
I think I have changed the options the right way.

sidebar a (left) - main - sidebar b (right) should be shown.
But there is sidebar main - a (left) - sidebar b (right) on my screen.
sl-pfandhaus-berlin.de/

I solved it by myself. I had to assign the layout to menu items.

Problem solved.