Create your pages separately in Xara Designer Pro. Arrange them in reading order, let’s say page 1, 2, 3 and 4 for a simple 4 page booklet. Export to PDF (File > Export PDF) and then open the PDF in Adobe Acrobat Reader.
Click the Print icon and select the Booklet option in the Print settings dialog. Set Booklet subset to Both Sides and Binding to Left.
You should then see a preview in print ready order: Page 4 and 1 (the front and back of the booklet) and page 2 and 3 (the inside spread).
If you want the content to spread across your inside pages of this 4 page booklet, including the fold and binding, then set that pair of pages to double page spread in Utilities > Options > Page Size. Make sure you uncheck ‘All pages in document the same’.
So then in Xara you should see:
And in the PDF preview:
This method is great for small booklets such as this, but Xara can’t account for the width of bindings in larger publications. However if you want to take binding widths into account then you can do it yourself in the design of the pages, and if you want to ensure that content spreads across printed pages and the binding width (such as a magazine outer wrapper) then it is best to make a custom sized single page of the required size, rather than using the double page spread feature. If you do this on just one or two sheets in a document make sure you turn off 'All pages in document the same' in the Utilities > Options >Page Size tab.