Create your document as normal using your default page size, usually A4. When you want to print it, select File Print. From Options select Brochure and from Properties select Landscape. Then from Options, select Brochure.
That's all! Your booklet will be printed on landscape A4 paper which can be stapled and folded to make an A5 booklet with the pages in the correct order. If your printer can print duplex all the better. Otherwise you will have to turn the pages over manually.
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