layout is not working

dear sir,
first big thanks for sharing this theme. that is what I want. very graceful and helpful. I have come across problems. when i set up a page. no matter which layout I choose. it always show me two siderbar. one is on the left and one is in the right. However, some pages i want no sidebar, some page i want right siderbar. some pages i want both.Not sure which layout i choose. it always show left and right side bars. please help how to fix.
thanks jonny