theres 2 ways of "properly" benching. one is the powerlifting style where you use tricep, shoulder, and back strength to help get the bar up. second is the "bodybuilder" style where arch is minimal and back is flat on the bench. the second technique is to focus more on chest. i train for powerlifting.
check google on powerlifting and bodybuilding, theres unlimited info on those 2 topics.