You can download your app to your mobile device and also view it in your desktop browser. Here is how:
Viewing your app on your mobile device
Visit this URL on your iOS or Android device. You can also hit the share button underneath your app and email or text the URL to yourself
You will first be asked to download the Yapp app and then your app will appear inside. See this video for more info.
Alternatively, you can download the Yapp app from your app store and log in with your Yapp account. This will give you admin privileges.
Click the my.yapp.us link from your desktop browser and you'll be taken to a web preview, where you can flip through the pages of your app. To get the native functionality (e.g. push notifications, uploading photos, offline access, etc.) use QR code on the right to open on your mobile device.