Upon a regular start from the Windows start menu or via desktop shortcut, the application starts with it's regular settings menu:

In case the configuration of the settings is already finished, you can disable the settings UI by starting the application with the argument of "-hide".
The application will be shown in the hidden icons in the task bar. While the SIPphone established a stable connection to the client, the shown icon will be green,
otherwise it will appear red. You can still open the settings UI by clicking the green/red circle.
In case you want to close the SIPphone application, right click the icon and choose "quit".