Determine the location where you want to divide the deck. For example, you may want to divide the deck evenly in half, or you may want one side larger than the other.
Decide how tall you want the screens to be. For example, you can use tall screens that humans can't see over, or you can use partial screens that you can see over, allowing for flow between the two areas.
Determine how much of the width of the deck you want the screens to cover. For instance, you can place a screen in the middle of the area that you want to divide, leaving the sides of the division open, or you can arrange screens across the entire width of the deck, from the outdoor wall to the deck post, to completely divide the area.
Choose durable screens that are made of materials that will withstand the elements -- bamboo or vinyl, for example. Opt for screens that suit your style. Purchase screens in the height you want and the widths you want them to cover. You may need to purchase a few screens to cover the deck to your satisfaction.
Set the screens up on the deck. Place the screens on the point of the deck where you want the division to be.