I bought mine from a funiture store that specialized in wicker chair recovering and rebuilding.
The guy told me to soak it in water until it is completely saturated then staple it in place, with the staples on the back of the grill near the edge. As it dries it will shrink and fit very taught.
I would recommend trying to install it on something that is throw away first to get the hang of how it works first, practice makes perfect. I wished I would have done that... lesson learned.
Chris... 8)