How do you customize the size of covers for z-folds and booklets

[Gutenberg II]

I'm new to Affinity Publisher. I'm building a Z-fold brochure and want the cover to properly align with the other panels.  How do you increase the size of the front cover and adjust printing marks of a z-fold? I'd also be interested in learning how to adjust page dimensions for multi-page booklets where the cover, initial and last pages have to be bigger than the central pages.

[Lee D]

For a multipage document you can adjust each using the Spread Setup, select the spread you wish to adjust and change the overall sizes. As Publisher doesn't have any templates for folded documents at the moment, I assume you have set one up just using guides. It will be a case of adjusting these to suit any adjustment required.