Set it up, I know it sounds obvious but once you actually take the time to set it up and play with it you will see there is not that much to it. There are some similarities between SUS and WSUS as well.
Just make sure you download WSUS 2.0 if you can, I think that is the one covered on the exams. WSUS 3.0 just came out not too long ago and there are enough differences with it that I would stick to trying to use 2.0 for exam studying.
It's one of those things that would be difficult to answer questions about without ever using it, but if you load it up and click around for a bit, you'll get it quickly. Also be sure to familiarize yourself with the related GPO settings.