1. Enable the plugin
Before you perform this tutorial please make sure Google App Engine Integration plugin is enabled in Settings → Plugins.
2. Create a new project
In order to create a project with support for Google App Engine integration choose Java Module in Project Wizard and click Next.
Now choose Google App Engine facet and specify path to the Google App Engine Java SDK folder.
The IDE will create an empty Google App Engine project.
3. Check the project structure
To make sure the project is configured correctly go to Project Structure → Modules and check settings of Google App Engine facet.
4. Run the application
Let's modify index.jsp page to output "Hello, world!".
Now we can run the application via the run configuration AppEngine Dev on the toolbar or via Run → Run 'AppEngine Dev' menu.
The IDE will run the application locally and open it in the browser.
5. Debug the application
If you run the application locally you can debug it just as a common web application via Run → Debug 'AppEngine Dev' menu or via the debug button on the toolbar.
6. Configure an account
If you want to upload the application to the cloud you have to create an application on https://appengine.google.com/.
When you have created an account on https://appengine.google.com/ you have to specify its name in your appengine-web.xml file.
7. Upload the applciation
Now you can deploy your application to the cloud via Tools → Upload App Engine Application. The IDE may ask you for the credentials.
While uploading the application the IDE will output logs to the Run tool window.
When the uploading is finished it will open the application in browser.