Using the program is as simple as copying the video's URL that you're interested in and start downloading.
This way you can easily access subtitles and if you'd like, you also get a direct link to download the original video to your computer.
TEDGrabber is a very interesting tool for the thousands interested in these popular talks that cover various topics such as art, science or politics. So if it is your case, don't doubt on giving it a try. And if it's not, maybe it's a good time to start watching them.