In the Package Explorer, right-click build.gradle and choose Run As > Gradle Build.

If the Edit Configuration window appears, enter clean build in the task editor, click Apply and then Run.

After refreshing your project, a zip file appears under build > distributions. This is a working extension that you can import into ThingWorx.

In the Package Explorer, right-click build-extension.xml and choose Run As > Ant Build.

After refreshing your project, a zip file appears under build > distributions. This is a working extension that you can import into ThingWorx.