1. You can run the TestNG script from the command line using Java.exe or use an IDE such as Eclipse. If you are using Eclipse, make sure to execute as a Java application, not a TestNG test, since the built-in TestNG runner for Eclipse doesn't support custom listeners (or not at time of writing).
2. Make sure to add the TestNG listener via either the TestNG XML file or the command-line.
3. Make sure that you have included the SpiraTest listener Java class as a listener in the TestNG configuration.