Windows Movie Maker is part of Windows 7. Earlier versions of Windows have it, but some features may differ. It is widely available and works on most contemporary machines. This is the program I show you how to use to make a video.
The basic steps to making a video are familiar to any author. You plot the video so it is around three minutes. Then you locate photographs to illustrate the plot. Some free resources are mentioned in the pamphlet. Then you put the photographs in order, put in titles and captions, and time the whole thing. Add an MP3 file of music, click the auto movie feature, and watch as it all becomes a video. All that is left is to tinker a bit with the timing, then upload the video to YouTube and publicize it.
The pamphlet includes screen shots so you can see exactly what to do each step of the way. Everyone should be able to construct a simple book trailer using these instructions. You can see the trailers I did for Mom at my YouTube channel.
I hope this pamphlet is useful. It is part of my series of POPCORN BOOKS: BITE-SIZED GUIDES TO THE UNIVERSE. What other topics do you need help with?