Instructions for all devices up to and including Android 10.
For newer devices, please refer to these instructions.
The first step is to download the eduroam CAT app from the PlayStore:
https://play.google.com/store/apps/details?id=uk.ac.swansea.eduroamcat
All security settings and the certificate are automatically set up via the app.
When you open it for the first time, you will be asked for location access. If you allow this, the quickest way to get to the settings of Bielefeld University (if you are located nearby...