Since the dvd is on a recordable disk it has no encryption like you see on commercially made disks. Therefore it is relatively easy to make copies if you have a dvd writer (drive) in the computer.
First get a free burning program called ImgBurn. www.imgburn.com
Install it into the computer. Now put the dvd disk you want to copy into your drive.
Start ImgBurn and you will see a pop up window giving you options. Click on Create image file from disc. What you are doing here is creating an ISO file of the entire disk and putting it on the hard drive.
Here is the guide for this process: http://forum.imgburn.com/index.php?showtopic=6379
Now, once you have made the ISO, you can burn it to as many disks as you want, also using ImgBurn. Here is the guide for burning the ISO to your blank dvds: http://forum.imgburn.com/index.php?showtopic=61
I advise setting burning speed in ImgBurn to 8x. You should use good quality disks, like Verbatim brand.
Welcome to the forums, and let us know if you have any questions or problems with this procedure.