Screen for Dummies

Why do I have a big dragonfly in the middle of my patio screen door? Because last summer I walked right into the screen. Didn't even see it. Left a nose print. So, I found this up at Rural King (sort of like a Tractor Supply store) and it has two pieces -- one for the outside and one for the inside of the screen and both have magnets on the back. I placed it right at my eye level so I'm sure to see the screen now.