My guess is that you use it like Windows Explorer. The right pane at http://a.fsdn.com/con/app/proj/discfit/screenshots/306607.jpg has the set so you would run your CD/DVD recording app and then make a Data DVD then select the set and then lasso all the files or try control+A and then drag and drop them into the pane on the recorder app that allows dropping from Explorer.

Again, it looks abandoned so hope this helps,
Bob