If you have never tried using automatic dictation software, then here's an easy way to do so. Use your web browser to visit www.talktyper.com and you're ready to start speaking.
You'll need a supported browser (Chrome is recommended), and you'll also need a microphone on your PC of course. Then just start speaking, one sentence at a time. Your spoken text appears in the top half of the window, ready for you to edit if required, and then to copy down to the main document in the lower half of the window. Once you've assembled an entire document or letter, you can print, email, or copy it to the clipboard for subsequent use.
Talktyper isn't the best dictation software I've ever used. And because it sends your speech to a remote server in order to deciper, it's probably not the most secure either. But it's quick, simple, free, and a great way to try out the technology if you've never used such a thing before. And it'll keep the kids entertained for hours too.