To modify that file, I recommend yo install 2 apps.

1. rootsh
2. leafpad

Then launch to xterminal app.
From the prompt, type the following.

root
leafpad /home/user/.config/sibplayer/SiBPlayer.conf

It will launch leafpad app with that file.
You can modify the file like notepad then just save. Done.
You can now close the app and also xterminal.

--

To delete that file:

rm /home/user/.config/sibplayer/SiBPlayer.conf

FYI - Just like DOS prompt in WIndows, you can press "Tab" to complete the paths for quicker navigation and less syntax errors.