Patch Tuesday is the day of the month that Microsoft releases the month's security updates (second Tuesday of the month). This month is a doosie, so it's more important than usual.
(Yes, I know it's Thursday. No, it's not "Patch Thursday." I've been busy.)
Windows Update will do everything you need - all you have to do is make sure its turned on. There's a great tutorial over at James Madison University, that will walk you through getting it set up. Recommended.