It should already be active without having to "turn it on" at least it is on my hp laptop... You can check it by opening the "sound" options in the "control panel" and clicking the "recording" tab, you'll then see the "integrated microphone array" is active by tapping on the laptop or making noise...
BUT if your wanting to know how to actually record something using it then open the "programs" folder in the "start menu" and check inside the "accessories" folder for the "sound recorder" program...
BUT if your wanting to know how to actually record something using it then open the "programs" folder in the "start menu" and check inside the "accessories" folder for the "sound recorder" program...