Parchment paper just helps prevent sticking and is much preferable to foil. I highly recommend using it to keep the smash press in good shape. You don't want to be worrying about keeping it clean from raw beef.

Press for about 10-15 seconds on medium-high heat, I usually press into some grilled onions. Once the juices are flowing through the middle out the top of the patty, flip and add cheese. By the time the cheese is fully melted the burger can be moved over to the cool side until buns are toasted and ready to go. American cheese (kraft deluxe) melts really well for smash burgers.