The reason they have a piece in progress is because they are just showing you the knit stitch. Each video shows you a specific technique, not the whole process. If you want to see a demo of someone doing it start to finish view the Demo videos.
Demo using English Method - English Method means you hold the yarn in your Right Hand
Demo using Continental Method - Continental Method the yarn is in your Left Hand.
The Demos show you the techniques in the project, not how to do each technique. For that you view the individual videos on how to Cast on, Knit, Purl, etc...