I'm assuming you are referring to WindowBlinds? If so, you'd need to purchase either the WB program, or Object Desktop, which includes WB and other customization programs. https://www.stardock.com/products/odnt/
Now you may be wondering why you'd need to purchase these programs? Simple truth is, we purchase all sorts of things that we either want or need, and either way, quality doesn't come for free. It's really a small fee for someone who's serious about customizing their PC.
Stardock is not trying to screw anyone. They are a business, and they sell software. It takes tons of manhours to program the software. I for one have no problem paying for it if I want it.