I have a ball with physics that falls down when the game starts. I would like to be able to reset it to its location before it falls by hitting a key on the keyboard. I am new to Unreal Engine so I’m not sure how to do this.
Hey @MelonTheCuber! Welcome to the forums!
So on the ball actor you can use “Keyboard ___” and fill in the blank with the key you want, and use that event.
On BEgin play, you want to save the location of the ball.
When you press that button, use Set Location with Self as the input object, and use the variable you saved on begin play for your location to set to! 
Should be as simple as that. Let us know if you need more info!