The discovered attack works just like discovered checks. In a discovered check you move a piece which reveals a piece behind that is attacking the king. The discovered attack is similar to that only that there won’t be any checks involved.So, when you move a piece, the piece behind it will be creating a threat which means that we will be discovering a piece behind that can create a threat for the opponent. One interesting thing about this is that the piece that is being moved can also become a threat on its own.Which means that in one move we are creating two threats for the opponent. Since this is a double threat at the same time, it becomes very difficult to defend yourself against such kind of a threat. So, with some intelligent moves, you can track your opponent pretty nicely.