An excellent way to provide an overview is through a video that captures screen content in real time and provides your voice explaining that content. Two software programs, which are both easy to use, can do that: Jing and Camtasia.
Jing has the advantage of offering a free version. Yes, it limits videos to 5 minutes or less, but for many occassions, 5 minutes is sufficient. In fact, many online instuction guidelines recommend organizing captured lectures in segments of no more than 15 minutes.