Turning a video from your computer into a DvD requires encoding it which means you will need to download a software. Paid software is obviously best, but here is one that I found to be the top freeware for DvD conversion:
http://www.dvdflick.net/
And here is a viddeo tutorial on how to use it:
http://www.youtube.com/watch?v=4v3M-yTZufs