The photo above is a prime example of a under exposed picture,in order to do that you need to adjust the exposure so that you take in more light if not all of your pictures will end up like this.unless your in a well lit space otherwise you may have to lower the exposure.

This image below is an example of a photo with a slow shutter speed,in order to have a proper photo with movements in it you need to have a faster shutter speed. If you do not increase the shutter speed it will look like the photo below.