You have to press the home button and the button that you turn off with at the same time. (That's how you do that for apple devices) and then you press the camera thing and then you look at your pictures that you've taken and select the one you want.
If you are on Android or PC/Mac you should be able to hold your finger on the image (touch screen) or right click the image and either way you do it, there should be a pop up box. Select "Save Image" or "Save Image As" and you can save it to your camera roll or folder of your choice. If you have a iPod, iPad, or iPhone then you can do what lovepink8800 or OMGitsbrittnayyy said. If you do it that way the screen should fade to all white then fade back in within 2 seconds. If the volume is turned up you should also hear a sound of a camera shutter closing