There are a few different variation of bench pressing. I would advise to watch the video linked to have to general understanding first of how to do bench press normally. Besides gripping the bar at shoulder width, one may grip the bar wider of closer then shoulder width. Do not go to wide of narrow because this may cause injury. Start slower if you want to change your grip style. The wider you grip, the more the chest muscles will be worked and the more narrow you grip, the more your triceps will be worked.