This is a recurrent question from people not reading the Writer Guide to at least understand how different LO Writer is from M$ Word. There are lots of questions with clear answers on this site. They can be accessed through the search tool with key like “page numbering”.
You must understand that your document is divided into homogeneous parts. This “homogeneity” addresses the characteristics of the pages (“geometry” defined by margins, header, footer, “parity”, …). These defining properties are recorded in a page style. Parts formatted by a page styles are separated by a special page break, namely
Manual Break which allow to specify both the page style to use after the break and the starting page number of the new part.
This is not convoluted at all. It is a direct application on the principles chosen to drive the Writer application. The principles are styles and, contrary to Word, they are present everywhere: paragraphs, characters, pages, frames, lists. Master the styles and you tame Writer.