Testing your app is as easy as returning from the coding section of the platform to the preview/design section where you designed your page on the first page.
Keep in mind that in this section there are two modes. The "play" mode is for previewing the design plus running any code written in the coding section. The "edit" (pencil) mode is for previewing only the design:
Before publishing your app you need to specify the main component or page. This is the "entry point" or where code execution will start from. At the right of the project name, there is a menu button and you should click on the "Edit" item.
That opens the "Edit Project" dialog box where you need to set "Question" as your "Main Component".
After saving, the name of the component ("Question") becomes bold and gets square brackets around it.
Publishing the app is super easy. Open the project menu once more to see the options for publishing to the web and mobile devices:
The "Publish Web App" option will provide a unique address for your project that you can share with users. The pop-up window will look like this:
The "Build Android App" will initiate a process of building an Android app. In the end, you will be able to download the APK file or scan the displayed QR code with the camera of your Android phone or tablet.