The simplest page numbering is to have the same style in the same position on each page. So, if you have a document and wish to number the pages:
Ribbon → Insert → Page Numbers → Bottom of Page → Plain Number 3 (say)
The pages of the document are now numbered consecutively from beginning to end with the numbers placed in the bottom right-hand corner of every page. Note that by convention page numbering begins with number one on the first odd page so that all odd pages have odd numbers and even pages have even numbers.
Most authors, although not all, format their page numbering so that on even pages the number is in the bottom left-hand corner creating a mirror image of the numbering in the odd pages.
Page numbering of a book is more complicated in part because some pages in the front matter are not numbered and the preface and or introduction have Roman numerals and so need to be separated from the main part of the book with its Arabic numerals. As with headers/footers, sections and the Link to Previous selection are key to successful pagination.
Taking British Isles Weather & Climate as an example the front matter of that text consists of eighteen pages, partly because of a very detailed contents section and because it has a two-page preface and two-page introduction.
The preface of this book, which is Section 4 of 24 sections, has two pages and that is followed by the two pages of the introduction (Section 5). To number these first parts of the book place the cursor in the footer of the first page of the preface and proceed as follows:
Ribbon → Insert → Page Number → Format Page Numbers → Number format → (select lower case Roman numerals) → Page numbering → Start at (select i)
(continue as for the top diagram in this page)
Ribbon → Insert → Page Number → Bottom of Page -> Plain Number 3
i appears in the bottom right-hand corner of the first page of the preface. The first page of the introduction should have a similarly placed iii
if it does not it is almost certainly because Link to Previous has not been selected
Select Link to Previous and iii appears in the correct place because the linking allows the continuation of the numbering.
The next step is to set up the even page numbers which have to be formatted separately because they are going to be placed in the bottom left-hand corner of the page as opposed to the bottom right-hand corner for the odd pages.
Go to the second page of the preface, ie the even page immediately following page i.
The process is the same as for the odd pages with one key difference:
Ribbon → Insert → Page Number → Bottom of Page -> Plain Number 1 (not Plain Number 3)
ii will then appear in the bottom left-hand corner of the first even page of the preface.
The last page of the introduction should have a similarly positioned iv
Again, if it is not there, select Link to Previous
Now you need to number the main part of the book using exactly the same methodology as for the preface / introduction but using Arabic numerals.
All the odd pages should have consecutive odd numbers in the bottom right-hand corner. If they disappear at some stage then check the Link to Previous selection in the footer of each section.
All the even pages should have consecutive even numbers in the bottom left-hand corner. Start on the first page after the first odd page and remember if they disappear at some stage check the Link to Previous selection in the footer of each section.