The sights above are both front and rear in one. You don't need two separate sights. The large assembly is attached to the slide no different than two separate sights are. Align the red "front" between the black rears and you're good to go. I think the idea behind it is that you can't see the red front unless you have the slide/pistol properly oriented(parallel to the ground or the shooters eye). Personally I think its a gimmick. Its simply front and rear sights in one which doesn't change the dynamic of sight alignment. Its awfully small and red is a difficult colour to pickup compared to green. Focus on the fundamentals and practice your draw, and the rest is irrelevant.
TDC