How do I render a Video?

What options do I put? I mean do I add .avi to the end of the file name and something else to the target option or what?
I watched so many tutorials and I still can’t figure it out.

Select .av in the file extension.
Select ffmpeg as target
Click on target parameters button (now enabled once you select ffmpeg)
Set your desired video codec default selection is ok.
Set video bit rate to 2000. It is more than enough for normal cases.