In basic mode you may select output file name, set more format options (e.g. output codec or JPEG image quality) for selected format and START joining all input files into one output. You may see selected output codec name below output file name.
NOTE: Output codec will be set same with last inserted file. In case you want to set another output codec use Format options... button.
Also you may click on Show preview button to view the preview during output process.
In advanced (opened) mode you may set much more output options. You may easy select output file format, set resolution for output file, set output file frame rate, let output file to keep original duration and set output audio quality.
Advanced options >>> button allows you to set Wiagra Video Joiner priority.
Also you may minimize Wiagra Video Joiner during joining files. In this case you may see joined percentage at Windows task bar.