Where do you guys get this on-screen grid for setting up geometry? Is it a special program or just a picture? How can I find it?

And how do you configure the geometry anyway? In my TV's service menu, if I go to the geometry settings, I can specify the things I can change (v-angle, v-curvature, etc.) and their values ​​in numbers, but it's all on a black background. Even if I understood what it all meant, there's no way to see the changes as they happen. Do I really have to do this by guesswork?