How to record audio over Powerpoint/OpenOffice slides? Many times I've seen videos of people talking while presenting their slides. How is that done on a Mac?

I know that I can do a screen recording with Quicktime, and I notice there are two options New Screen Recording and New Audio Recording.

But there is no New Screen+Audio Recording.

Thanks for any help.
You can actually record audio with a Screen Recording in Quicktime, you just need to set the proper option. Just open a new screen recording (⌃⌘N), then click the white triangle:



You'll get a popup menu with options to choose which sound input you want to record from:


Select the appropriate sound device, then start the recoding, and you'll be able to narrate as you record your screen.