Each Casio watch is different, however, instruction manuals for each timepiece are readily available through the Casio website at support.Casio.com. You will need the model number of your watch, which is located on the back cover and is usually 4 digits long.
If your watch is digital, you may need to use the buttons on the left and right sides of the face. Follow the instructions on the manual for best results. An analog watch will require you to pull out the crown on the right side of the face. Twist the crown in the direction you want the hands to move and set accordingly. Push the crown back in to confirm the set time.
There may be other features of your watch to set. Some Casio watches display not only time, but also date as well. You might have to set the alarm feature on your watch, and it may have a timer and stopwatch you'll need to familiarize yourself with. Sporty versions offer world time, temperature and even a compass.
For a detailed explanation on how to set your Casio watch and all features/functions, look up the instruction manual specific to your model directly on the Casio website. Manuals are available in PDF format for easy printing or saving to your computer.