To Set up your VPN to the TU-Vienna just go the Homepage https://vpn.tuwien.ac.at/ . Here you have to log in with your default TU-Account(pic1). After you logged in, the homepage will try to automatically install the Cisco Anyconnect Client. If your browser asks you to allow anything on this page, please do so.
In the case that the automatic installation didn't work(pic2), the homepage will give you a direct download link for the programm. Download and Install it.
Start the program. int the field "Connect to:" type in "vpn.tuwien.ac.at" and press Connect. Now type in your username and password. With this you should be connected to the network of the TU-Vienna.
Be aware, that local network connections to printers or other Computers are not available while using the VPN-Tunnel!