A5 pages in book but printer has A3 only

I have a book which has 116 pages in A5. I want to print it. But the printer has A3 printing only. How do I set it up in CorelDraw (version 16 or 17) ? He told me to use a layout of 12x18 inches. The pages are all in jpg image format. There are 116 jpg files corresponding to each A5 page. How should the page layout on each page be so that it is printed properly on the A3 pages by the printer? Thanks.