In the previous tutorial, we learnt to edit video in Blender. Now we will learn how to export the video out of Blender into a self-contained movie file. This is also called "rendering" video, because we are causing the CPU(s) of the computer to take the frames that you've edited and write them out into a new file. This can be a long process if you have added a lot of transitions and effects, and will be entirely dependent upon how fast and efficient your CPU(s) is/are.
Before you commit to anything you may want to watch and listen to your work. Um...this is helpful while editing too...
Have no idea what codec and resolution to choose? Go over to hackerpublicradio.org and listen to Klaatu's series on Video Encoding.