The configuration profile isn't signed for technical reason. You can have a look on the profile to be sure, it will not do anything unexpected.
Enter your UserID and add @tu-clausthal.de behind it, so it looks like the following: „mmus17@tu-clausthal.de“ . Then enter the belonging password and click on Install.
After the installation is complete, you´ll get a summary of all changes that were taken to your system.
Eduroam is installed successfully.
Check the Installation
In your System Settings below Network / Advanced you can check the tab 802.1x, if the profile „WiFi (eduroam)“ installed correctly.