The following video shows a demonstration of a push press:
A push press may be done with a barbell, dumbells, or anything of moderate weight (bowling ball, box, etc.) Stand up straight and lift the weight up onto your chest to the starting position of the movement. Your elbows should be under the weight, which will be supported by the pads of each hand. To begin the push press, bend your knees slightly, then explode back up and use the momentum to press the barbell up over your head, locking out your elbows. Lower the weight back down to your chest. That’s one rep.
I am a high school track and field coach that works with athetles that compete in throwing events (shotput and discus). During our weight workouts I emphasize olympic lifts like the power clean. I tell my athetles that if you were to only have time to perform one lift a week, the power clean would be the lift to do. I find that the power clean does work multiple muscles and it also seems to increase our athetles quickness/explosiveness which is key in throwing events. I personally make sure that I inclued power cleans in my own weekly workouts. I however do a variation called the hang clean. The hang clean is like the power clean, but it starts with the barbell at mid-thigh. The hang clean puts a lot less stress on my back, but allows me to still have a very explosive lift.