Because this exercise is the video version of Morning Pages (see Julia Cameron's fabulous book The Artists Way) the BEST way to approach your camera time is to just be present, say whatever you're thinking. You're not going to be sharing this with the public, that's the point, so literally just say what's on your mind. Even if it's your shopping list or a grumble.
I know starting out can be tricky, so use these topics as a jumping off point. Do your best to stay unselfconscious and just prattle on, pretend you're talking to a best friend or to a pet or, ideally, your diary or journal.