After several failed attempts, I created my first video using YouTube's video editor and was able to successfully create a screen cast of my process!
Here is my first mash-up video:
Here is my screen cast, explaining how to create your own mash-up video.
Here is a copy of my copyright dispute! While the original YouTube video was approved, the screen cast of me teaching how to create the video was flagged for using third party content, the song "Hot Buttered Popcorn," which was featured in the clip. This was a terrific lesson on the nuances of copyright and fair use.