In the page, you build it like a regular webpage with the header and footer, and in the middle, you place a content placeholder object, a container that will hold that space in the seperate file you created.
default.aspx - reference the container in the master page in your content page, and content below will be injected into the master page.
<asp:Content ID="Content3" ContentPlaceHolderID="SiteMap" runat="server">
<!-- Encode the Sitemap Content of the Page -->
Some content such as words or pictures in your seperate file
Last Visit: 31-Dec-99 18:00 Last Update: 24-Aug-16 2:45