You open the Add Web Service Operation dialog box by right-clicking on the Web Services node in the Services window and choosing Add Web Service.
The Add Web Service Operation dialog box lets you add a WSDL file to the IDE.
Troubleshooting
Check your proxy settings, if error messages such as the following are returned:
org.netbeans.modules.websvc.registry.ui.ReflectionHelper.callMethodWithParams(ReflectionHelper.java:449)
For details, see Setting a Proxy for Consuming a Web Service.