A great question and here is some information for you. Good luck!
Hi Valerie, check out this link, it may be helpful
Since some are just showing pictures and not telling you HOW to put them up....they come in sheets at Home Depot. Plastic and wood. The plastic comes in two sizes. If not the size you want mark the height and zip off the excess with a circular saw. The easy part with the plastic lattice is you can use electrical ties to anchor them to the existing railing. You feed one end into the other wrapped around the railing and fed thru the lattice then cut off the excess. Otherwise drill a hole and screw to top and bottom of every couple of rails.