Print, and install with zip ties or screws. It is made to fit on Greg's X-Carriage with Kühling's LM Holder. You can either install it with a little gap (not a bad thing, due to a slight venturi / bernoulli effect it give slightly more air flow) or what I do is use a hot air gun to soften and mold it around the Tommyc carriage.

Because it is square, you can scale it, to fit your own fan size.