Sections can be used to change the numbering scheme in some pages of the document. This is really common in books or even in some magazines where the preface or the appendices use Roman numerals, whereas the main content uses the usual Arabic numerals.
Let's say we have a 100 pages document containing a 10 page Appendix and a 3 page Preface beginning after the cover pages. Each of them will begin at 1 but the Preface and Appendix will use Roman numerals.
Tip
Book numbering scheme
Usually, in books, the cover page is not numbered. So, if you create a single Scribus document for a book, containing the cover, you'll certainly need to define a section beginning at Page 3.
The Document Setup window (File menu) has a Section part in which sections can be managed. Each has a default section beginning at Page 1. Just click on the Add button to create new sections that you will set as you like.
The result is a table of properties. You just need to understand what the columns mean:
Name...