First, measure the size of window,Then, cut the blind to size, Next, clean the window, Finally, attach the hook & loop dots and tapes to the frame and stick the blind on the frame, Also, this blackout curtain is not like usual curtain, it can be easily cut to any shapes you want to perfectly fit various windows.(When cutting, please increase the size of the blackout lampshade to achieve more effective light blocking effect) Security Window Film