How do you launch or install the Eclipse XSD editor?
According to this it seems it should work out-of-the-box. I created the XMLExamples project and when I
XMLExamples
Which Eclipse package did you install? The XSD editor isn't included with all of them. If you click on "details" for any package, you can see the included features. The one you're looking for is org.eclipse.wst.xml_ui.feature.