Wondershare 3GP Video Converter's main window displays a list where you can add video files that you want to convert. You can set here the output format and path and you can also preview the video file 

The Edit menu allows you to apply various effects on your video, like Brightness, Contrast, Saturation. Here you can aslo set the default volume for your video 

The Options window displays few options about Language and Skin and about the Snapshots, for which you can select an output folder and an image format 

And here is an example of how an *.avi file has been converted into a *.3gp one. If you want you can shut down the computer or open the output folder after conversion