1) design in scribus
A5 pages, folded. How many pages? Multiple of 4.
2) export to PDF
compress all images to 300DPI
include all fonts
3) open PDF in Document Viewer on a Ubuntu forest machine
a) file ..print setup ... A5!
b) file .... print ....tab marked general. All pages, 1 or more copy
c) tab marked setup .... 1 page per side .... paper source tray 2
d) tab marked advanced .... duplex on, Combination booklet.
cross all appendeges, knock on wood.