Hi and welcome here @CDF,
if Nero is installed on your PC then just open a new compilation (CD-ROM ISO), put your files in the compilation and start burning. If you are really new and you have no Idea waht to do it's might better to work with Nero Express (wizard). Just click on the Nero Express button.
The last thing I want to add is that I don't see a real requirement to backup Nero on a CD, you can download it again as often as you want. Also note that Nero is updated to a new version all 1-2 month.