To create the Data Form Web Part, you first need to have your xml file (Donut1.xml in our example) uploaded to your site, in a document library. Then follow these steps:
1/ Create a Web Part page, and open it in SharePoint Designer.
2/ Display the Data Source Library (Task panes | Data Source Library) >> screenshot
3/ Under XML files, find your file, and in the context menu select "Show Data" >> screenshot
4/ Select the fields you want to display in the form (in blue in the screenshot), then select Insert Selected Fields as | Multiple Item Form >> screenshot
Your Data Form Web Part is now ready. You can further customize it in SharePoint Designer, and export it for reuse in other pages of your site.