Step 1 - Clean the target surface of the window, and make sure no stain is left. Step 2 - Measure your target window glass size and record, cut the film and leave an extra 2-3 cm on each side for easier adjustment. Step 3 - Tear off the protective backing liner, spray a lot of water both on the window surface and film. Step 4 - Apply the film on the window glass, squeegee away air bubbles and water with a scraper or card. Step 5 - Trim excess film with a sharp razor or knife.