Our first step is to create a sitemap file. In this example, let's say we have a Sidebar at the left of our website which needs to expand/collapse. Here is how to create the sitemap file for this sidebar.
In Visual Studio, on the right (solution explorer), hover over the name of our site, right click and select Add -> New Item. Or just press Ctrl + Shift + A. The Add New Item popup box appears.
In the Add New Item popup box, select Sitemap and click Add. Lets rename this to Web.sitemap.
Each collapsable section will start with siteMapNode and end with /siteMapNode. Fill in the URLs and names of our pages.