See the attached example file for instructions, and well, an example. I have found the way to start page numbering at an arbitrary number, like many are asking for.

If you need further customization for your pages, right-click on the Page Style name and choose Modify. You now have page numbers starting on page 2 with “2”. Select the menu Insert -> Fields -> Page Number. Use the tab key to locate the cursor where you want the page number to be. Click on the footer to place the cursor in it. Insert a footer by choosing Insert > Footer > Default Style from the main menu. For the simplest case, go to the menu Insert -> Footer -> Default (or Insert -> Header -> Default if you want page numbers at the top of the page).This applies the First Page style to your first page. Click on the Page Styles button at the top of the window. The Styles and Formatting window will open.

Click on the Styles and Formatting icon on the Formatting toolbar.These steps will apply two page styles to a document – one for the first page with no footer, the second for the rest of the document with a footer and page number.

Openoffice add page number to footer