The first step is to download the geteduroam app from the App Store:
-> https://apps.apple.com/de/app/geteduroam/id1504076137
All security settings and the certificate are set up automatically via the app.

When opening for the first time, search for"Bielefeld" in the search field and select Bielefeld University.

The personal login details are now entered here:
User name:
-> BITS-Loginname@uni-bielefeld.de
Password:
-> BITS password (network password)
Then click on Log in .

The app can now be closed.
The app was only used to set up the WLAN. As a rule, the smartphone will then automatically connect to eduroam.