As with any exercise, if you’re new to it, you need to begin at the easiest level.
The push up on the bench or a step with your knees in real close to the bench; supports most your body weight so you’re pushing up with minimal resistance. As you get stronger, you can move your knees further away from the step adding to the resistance. Then you can progress to the toes & finally on the floor.
Using the Bar and some weights rather than the bench, adds to working all your stabilizers. Though the elevation of the arms works the chest a little less, you add to shoulder & abdominal work as you “balance”.

Try them or a combination of all three to spice up your push up.
Disclaimer: As with any type of physical activity, it is advised you warm up for 5 minutes before commencing exercise, followed by 5 minutes of stretching upon completion. These exercises are designed as a basic guide and professional consultations should be taken before commencing any exercise.