Just open the Camera App on your iPhone and point it to the above shown QR Code. The yellow markers indicate that your iPhone detects the code and shows a yellow notification with the text "billyard.de". You can simply click this notification to open the WebApp in Safari.
If you have an older iPhone without QR code feature in the camera app or if you open this page on your iPhone, you can also launch the WebApp manually - more in the following paragraph. Just click on the iPhone app with the compass illustration.
This app is the Safari web browser which is the application that allows you browsing the Internet on your smartphone.
In the next step, simply tap the Safari address bar to type in the website (webapp.billyard.de).
You almost made it. To access our WebApp simple and easy, you can save our app icon to your home screen - just like you know it from your other apps.
Just click on the Share icon at the bottom of Safari. This icon is enlarged illustrated here: