Invoke the Windows tools menu by pressing the Windows key + x. Within the following menu, choose Systemsteuerung:
Or: Click on the windows icon in the botom left and then type in "systemsteuerung" - which will display the 'Systemsteuerung' as an app to be opened. Open it.
Within the Systemsteuerung click on Netzwerk und Freigabecenter, then Neue Verbindung ... einrichten.
Next choose the menu item Verbindung mit dem Arbeitsplatz herstellen:
Click on Internetverbindung (VPN) verwenden:
Enter vpn.uni-mainz.de into the input field Internetadresse:
For Zielname you may enter a self-chosen name which you will later use to choose this VPN connection, e.g. Uni-VPN or VPN connection.
All other checkboxes can be left unchanged. Click on Erstellen .
In the next window you have to enter your JGU account user name and your password. You should only check the option 'Dieses Kennwort speichern' if you are the only user of this computer.
Finally, click on Verbinden. The VPN connection is now established.