Please download WinSCP from https://winscp.net/eng/download.php and use at least Version 5.8, because file locking won't be functional otherwise.
Start the Software with a double click and follow the installation wizard.
Start of WinSCP
After starting WinSCP, the following window opens:
Choosing the Settings
Be aware tha websites are being migrated at the moment. Webupload URLS can be different depending on your websites' status: https://maintenance.rz.rwth-aachen.de/ticket/status/messages/15-web-server
Use WebDAV as File Protocol and choose webhosting-upload.rwth-aachen.de as host name. Set TLS/SSL as encryption and type in username and password:
Go to Advanced and type in the path to your webspace as remote directory (also retrievable via Webhosting Portal):
if the site name contains periods, they should be replaceed with a hypen, e.g. it.center → it-center
Accept the settings with OK and start the session with Login.