You most likely did a push-up at some stage in your life before beginning CrossFit, but you may not have done the full spectrum of motion pushups we use in CrossFit. Your arms should be absolutely straight at the top, and your chest should be in touch with the ground at the bottom.
5 rds 30/20 Cal. Assault Bike 25 Push Ups 25 Ring Rows* * for the ring row, set feet directly underneath pull up bar. Top of the ring should line up with the arm-pit.