End the complexity. Just order the lunch.
In the app you can easily order or cancel your lunch. It is an unofficial app made by a student. In the background it uses the official canteen website.
To use it, you must be registered as a guest at the school. They will give you credentials you can login with in the app or on their website.
Do you sometimes forget to order the lunch! This will save you! You can activate automatic ordering or enable notifications that will send you a message!