Nikon Slr Camera How Do You Turn On Flash For A Nikon SLR Camera?

How do you turn on flash for a Nikon SLR camera? - nikon slr camera

My brother is the only one who knows how to work the camera Nikon SLR, but when he on vacation, I was next in the series. Teaches the basics, but I've forgotten how to activate the flash. Someone please give me the answers!