You are a geeky/nerd loser in a private academy. You spend your time fantazising about girls and trying to get panty shots when you can. Maybe... however... if you work hard enough, and are lucky enough, you might end up in a better situation. One can never tell.
In order for you to be able to install this game, you need to enable (allow) installation of applications from unknown sources (Unknown sources) in the phone settings. Usually this item is in the Security section