There are multiple options available
to Test and preview Your Apps Before publication
In your App Editor on the right-hand side, you have a phone simulator (Previewer), called "Overview". It does not have all the native capabilities of a real phone, so some features are disabled, but you will be able to see and test your App and changes in real-time.
You can also use the WebApp version of your App to rapidly test it on any device. Navigate to the "Application" tab in your App Editor; under general information, you'll see your App's WebApp link, which you can visit on your device or mobile device's browser.