Put some strong nylon cord about 2mm diameter inside the window seal channel all the way around, then place the screen on top. From the inside, start pulling the cord straight up away from the screen, slowly and evenly while someone holds it in position for you with gentle pressure. This will pull the seal over the screen. You will stuff it up a couple of times before you get it, but it isn't hard. If your seal is real hard, perhaps lubricate it a little bit with silicon.
Toyota recommend using soapy water
