Taking a screenshot is not only a great way of saving a memory or achievement in a game, it's also a fantastic way of capturing what a problem looks like so that you can save and send it along to us!
Sometimes a picture saves a lot of time in explanation!
The way to take a screenshot varies from device to device, but here's a quick guide:
Hold down the Power and Home buttons at the same time. You'll see a brief white screen flash (and hear a sound too if you have sounds on) to tell you that it has taken a picture. Screenshots will be saved in your camera roll where you will be able to browse for them later.
Hold the Volume Down and Nook Home buttons in together for approximately two seconds. This may take a few tries to get right as the timing has to be quite precise! The screenshot will be saved and visible within the Gallery app.
Android Phones and Tablets
This can vary quite a bit from device to device, but usually is activated by pressing down the Power and Home buttons at the same time. The screenshot will be available to you usually within the photos application. If this is different on your device, you may need to do a web search for "take a screenshot on <your device name>".
Press and hold the Volume Down and Power buttons in together for approximately two seconds. The screenshot will be saved and visible within the Photos list on your Kindle, which you can browse to from the main apps screen.