You don't really need it its just a case speaker. Your Motherboard should have audio outputs where you will plug your speakers into. Your motherboard will have some pins on the outside where it fits if you really want to fit it. get a magnifying glass if you need to and look along the edges for the pins that say speaker next to them or else look up the motherboard manual which will tell you where exactly it can be connected.
Fast forward to Op plugging his case speaker into the audio port then wondering why games are quiet
check your motherboards manual Op, it will either show you where your casespeaker is (if it has one already) or where to plug that one into